SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    10630, 4882, 5438, 5332, 5477, 5531, 
    5218, 5346, 5472, 5238, 5255, 5268, 
    5280, 5292, 5303, 5315, 5322, 5366, 
    5401, 5404, 5416, 5427, 5445, 5454, 
    5485, 10171
  )

Query time 0.00047

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "12.63"
    },
    "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": 29,
      "rows_produced_per_join": 29,
      "filtered": "100.00",
      "using_index": true,
      "cost_info": {
        "read_cost": "6.83",
        "eval_cost": "5.80",
        "prefix_cost": "12.63",
        "data_read_per_join": "171K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "(`webmarco`.`cscart_categories`.`parent_id` in (10630,4882,5438,5332,5477,5531,5218,5346,5472,5238,5255,5268,5280,5292,5303,5315,5322,5366,5401,5404,5416,5427,5445,5454,5485,10171))"
    }
  }
}