SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    5215, 5298, 4373, 5088, 5231, 4754, 5173, 
    5312, 4773, 5244, 5197, 5320, 4786, 
    5256, 4807, 5270, 4820, 5282, 4834, 
    4848, 4866, 4884, 4903, 4933, 4987, 
    10182, 10183
  )

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "15.43"
    },
    "table": {
      "table_name": "cscart_categories",
      "access_type": "range",
      "possible_keys": [
        "parent"
      ],
      "key": "parent",
      "used_key_parts": [
        "parent_id"
      ],
      "key_length": "3",
      "rows_examined_per_scan": 36,
      "rows_produced_per_join": 36,
      "filtered": "100.00",
      "using_index": true,
      "cost_info": {
        "read_cost": "8.24",
        "eval_cost": "7.20",
        "prefix_cost": "15.44",
        "data_read_per_join": "213K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "(`webmarco`.`cscart_categories`.`parent_id` in (5215,5298,4373,5088,5231,4754,5173,5312,4773,5244,5197,5320,4786,5256,4807,5270,4820,5282,4834,4848,4866,4884,4903,4933,4987,10182,10183))"
    }
  }
}