SELECT 
  cscart_product_feature_variant_descriptions.variant, 
  cscart_product_feature_variants.variant_id, 
  cscart_product_feature_variants.feature_id, 
  cscart_product_features_values.variant_id as selected, 
  cscart_product_features.feature_type, 
  cscart_seo_names.name as seo_name, 
  cscart_seo_names.path as seo_path 
FROM 
  cscart_product_feature_variants 
  LEFT JOIN cscart_product_feature_variant_descriptions ON cscart_product_feature_variant_descriptions.variant_id = cscart_product_feature_variants.variant_id 
  AND cscart_product_feature_variant_descriptions.lang_code = 'en' 
  LEFT JOIN cscart_product_features_values ON cscart_product_features_values.variant_id = cscart_product_feature_variants.variant_id 
  AND cscart_product_features_values.lang_code = 'en' 
  AND cscart_product_features_values.product_id = 248 
  AND cscart_product_features_values.feature_id = cscart_product_feature_variants.feature_id 
  LEFT JOIN cscart_product_features ON cscart_product_features.feature_id = cscart_product_feature_variants.feature_id 
  LEFT JOIN cscart_seo_names ON cscart_seo_names.object_id = cscart_product_feature_variants.variant_id 
  AND cscart_seo_names.type = 'e' 
  AND cscart_seo_names.dispatch = '' 
  AND cscart_seo_names.lang_code = 'en' 
WHERE 
  1 
  AND cscart_product_feature_variants.feature_id IN (
    23, 21, 29, 28, 26, 25, 27, 36, 35, 32, 31, 
    42, 45, 44, 43
  ) 
GROUP BY 
  cscart_product_feature_variants.variant_id 
ORDER BY 
  cscart_product_feature_variants.position, 
  cscart_product_feature_variant_descriptions.variant

Query time 0.00253

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "282.20"
    },
    "ordering_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "grouping_operation": {
        "using_filesort": false,
        "nested_loop": [
          {
            "table": {
              "table_name": "cscart_product_feature_variants",
              "access_type": "index",
              "possible_keys": [
                "PRIMARY",
                "feature_id",
                "position"
              ],
              "key": "PRIMARY",
              "used_key_parts": [
                "variant_id"
              ],
              "key_length": "3",
              "rows_examined_per_scan": 158,
              "rows_produced_per_join": 52,
              "filtered": "32.91",
              "cost_info": {
                "read_cost": "22.20",
                "eval_cost": "10.40",
                "prefix_cost": "32.60",
                "data_read_per_join": "59K"
              },
              "used_columns": [
                "variant_id",
                "feature_id",
                "position"
              ],
              "attached_condition": "(`twebezli_Commercemodalpopup`.`cscart_product_feature_variants`.`feature_id` in (23,21,29,28,26,25,27,36,35,32,31,42,45,44,43))"
            }
          },
          {
            "table": {
              "table_name": "cscart_product_feature_variant_descriptions",
              "access_type": "eq_ref",
              "possible_keys": [
                "PRIMARY"
              ],
              "key": "PRIMARY",
              "used_key_parts": [
                "variant_id",
                "lang_code"
              ],
              "key_length": "9",
              "ref": [
                "twebezli_Commercemodalpopup.cscart_product_feature_variants.variant_id",
                "const"
              ],
              "rows_examined_per_scan": 1,
              "rows_produced_per_join": 52,
              "filtered": "100.00",
              "cost_info": {
                "read_cost": "52.00",
                "eval_cost": "10.40",
                "prefix_cost": "95.00",
                "data_read_per_join": "157K"
              },
              "used_columns": [
                "variant_id",
                "variant",
                "lang_code"
              ]
            }
          },
          {
            "table": {
              "table_name": "cscart_product_features_values",
              "access_type": "eq_ref",
              "possible_keys": [
                "PRIMARY",
                "fl",
                "variant_id",
                "lang_code",
                "product_id",
                "fpl",
                "idx_product_feature_variant_id"
              ],
              "key": "PRIMARY",
              "used_key_parts": [
                "feature_id",
                "product_id",
                "variant_id",
                "lang_code"
              ],
              "key_length": "15",
              "ref": [
                "twebezli_Commercemodalpopup.cscart_product_feature_variants.feature_id",
                "const",
                "twebezli_Commercemodalpopup.cscart_product_feature_variants.variant_id",
                "const"
              ],
              "rows_examined_per_scan": 1,
              "rows_produced_per_join": 52,
              "filtered": "100.00",
              "using_index": true,
              "cost_info": {
                "read_cost": "52.00",
                "eval_cost": "10.40",
                "prefix_cost": "157.40",
                "data_read_per_join": "40K"
              },
              "used_columns": [
                "feature_id",
                "product_id",
                "variant_id",
                "lang_code"
              ]
            }
          },
          {
            "table": {
              "table_name": "cscart_product_features",
              "access_type": "eq_ref",
              "possible_keys": [
                "PRIMARY"
              ],
              "key": "PRIMARY",
              "used_key_parts": [
                "feature_id"
              ],
              "key_length": "3",
              "ref": [
                "twebezli_Commercemodalpopup.cscart_product_feature_variants.feature_id"
              ],
              "rows_examined_per_scan": 1,
              "rows_produced_per_join": 52,
              "filtered": "100.00",
              "cost_info": {
                "read_cost": "52.00",
                "eval_cost": "10.40",
                "prefix_cost": "219.80",
                "data_read_per_join": "22K"
              },
              "used_columns": [
                "feature_id",
                "feature_type"
              ]
            }
          },
          {
            "table": {
              "table_name": "cscart_seo_names",
              "access_type": "ref",
              "possible_keys": [
                "PRIMARY",
                "dispatch"
              ],
              "key": "PRIMARY",
              "used_key_parts": [
                "object_id",
                "type",
                "dispatch",
                "lang_code"
              ],
              "key_length": "206",
              "ref": [
                "twebezli_Commercemodalpopup.cscart_product_feature_variants.variant_id",
                "const",
                "const",
                "const"
              ],
              "rows_examined_per_scan": 1,
              "rows_produced_per_join": 52,
              "filtered": "100.00",
              "cost_info": {
                "read_cost": "52.00",
                "eval_cost": "10.40",
                "prefix_cost": "282.20",
                "data_read_per_join": "88K"
              },
              "used_columns": [
                "name",
                "object_id",
                "company_id",
                "type",
                "dispatch",
                "path",
                "lang_code"
              ]
            }
          }
        ]
      }
    }
  }
}

Result

variant variant_id feature_id selected feature_type seo_name seo_path
1 TFLOP 164 27 S
1.23 TFLOPs 142 27 142 S
1.24 GHz 181 28 S
1.75 GHz 143 28 143 S
1.84 TFLOPs 186 27 S
2000 MB, DDR3 179 25 S
250 GB 138 23 S
3.20 GHz 166 28 S
32 GB 189 23 S
500 GB 139 23 139 S
512 MB, 700 MHz, GDDR3 163 25 S
8-core AMD 144 29 144 S
8192 MB, DDR3 140 25 140 S
8192 MB, GDDR5 185 25 S
AMD Radeon HD 5650 178 26 S
ATI C1/Xenos 162 26 S
AV-output 171 31 M
BD (Blu-ray Disc) 159 43 159 S
Black 161 45 161 S
Blu-ray 150 35 150 M
Bluetooth 187 32 M
CD 154 35 154 M
CD R 167 35 M
composite AV cable 173 42 M
CR RW 168 35 M
DVD 175 43 S
DVD 151 35 151 M
DVD R 152 35 152 M
DVD RW 153 35 153 M
Ethernet 149 32 149 M
HDMI 145 31 145 M
HDMI cable 157 42 157 M
Headset 156 42 156 M
IBM PowerPC 750 180 29 S
integrated AMD Radeon GPU 141 26 141 S
JPEG 170 36 M
MP3 169 36 M
Nintendo WiiNintendo Wii U 183 44 M
optical audio output 147 31 147 M
PlayStation 4 188 44 M
Power PC (3-core) 165 29 S
stationary 137 21 137 S
USB cable 158 42 158 M
USB x2 146 31 146 M
USB x4 182 31 M
USB x5 172 31 M
Wi-Fi (802.11b/g/n) 148 32 148 M
Wii U Optical Disc 184 43 S
WMA 155 36 155 M
Xbox 174 44 M
Xbox One 160 44 160 M
Xbox360 176 44 M