SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    216, 204, 210, 212, 211, 213, 209, 217, 
    215, 214, 208, 218
  )

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "20.08"
    },
    "table": {
      "table_name": "cscart_categories",
      "access_type": "ALL",
      "possible_keys": [
        "parent"
      ],
      "rows_examined_per_scan": 83,
      "rows_produced_per_join": 17,
      "filtered": "21.69",
      "cost_info": {
        "read_cost": "16.48",
        "eval_cost": "3.60",
        "prefix_cost": "20.08",
        "data_read_per_join": "46K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "(`atulecarter_atul_demo5`.`cscart_categories`.`parent_id` in (216,204,210,212,211,213,209,217,215,214,208,218))"
    }
  }
}