SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    424, 425, 426, 427, 428, 429, 430, 431, 
    432, 433, 434, 435, 436, 437, 438, 439, 
    440, 441, 442, 443, 444, 445, 446, 447, 
    448, 449, 348, 423, 235, 216, 204, 242, 
    229, 222, 251, 210, 168, 198, 166, 212, 
    176, 178, 190, 224, 255, 246, 167, 182, 
    175, 230, 220, 252, 197, 211, 213, 236, 
    185, 169, 243, 191, 247, 209, 217, 203, 
    225, 193, 223, 199, 215, 221, 214, 231, 
    240, 208, 179, 249, 253, 226, 186, 218, 
    174, 244, 219, 234, 194, 200, 180, 238, 
    232, 202, 227, 248, 187, 181, 195, 177, 
    228, 237, 196, 188, 241, 254, 189, 245, 
    250, 165, 170, 171, 172, 201, 263
  ) 
  AND category_id != 264

Query time 0.00104

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "23.60"
    },
    "table": {
      "table_name": "cscart_categories",
      "access_type": "index",
      "possible_keys": [
        "PRIMARY",
        "parent",
        "p_category_id"
      ],
      "key": "parent",
      "used_key_parts": [
        "parent_id"
      ],
      "key_length": "3",
      "rows_examined_per_scan": 113,
      "rows_produced_per_join": 55,
      "filtered": "49.56",
      "using_index": true,
      "cost_info": {
        "read_cost": "12.40",
        "eval_cost": "11.20",
        "prefix_cost": "23.60",
        "data_read_per_join": "146K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "((`twebezli_Commercemodalpopup`.`cscart_categories`.`parent_id` in (424,425,426,427,428,429,430,431,432,433,434,435,436,437,438,439,440,441,442,443,444,445,446,447,448,449,348,423,235,216,204,242,229,222,251,210,168,198,166,212,176,178,190,224,255,246,167,182,175,230,220,252,197,211,213,236,185,169,243,191,247,209,217,203,225,193,223,199,215,221,214,231,240,208,179,249,253,226,186,218,174,244,219,234,194,200,180,238,232,202,227,248,187,181,195,177,228,237,196,188,241,254,189,245,250,165,170,171,172,201,263)) and (`twebezli_Commercemodalpopup`.`cscart_categories`.`category_id` <> 264))"
    }
  }
}