SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    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 0.00053

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "20.28"
    },
    "table": {
      "table_name": "cscart_categories",
      "access_type": "ALL",
      "possible_keys": [
        "PRIMARY",
        "parent",
        "p_category_id"
      ],
      "rows_examined_per_scan": 84,
      "rows_produced_per_join": 84,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "3.48",
        "eval_cost": "16.80",
        "prefix_cost": "20.28",
        "data_read_per_join": "219K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "((`atulecarter_atul_demo4`.`cscart_categories`.`parent_id` in (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 (`atulecarter_atul_demo4`.`cscart_categories`.`category_id` <> 264))"
    }
  }
}