SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  cscart_product_descriptions.full_description 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    18345, 18346, 18347, 18348, 18349, 18350, 
    19542, 20113, 20119, 20120, 21943, 
    21992, 21999, 22000, 22413, 22414, 
    22418, 23717, 23730, 24175, 24176, 
    25619, 25621, 25969
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00059

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "18.44"
    },
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "product_id"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id",
        "lang_code"
      ],
      "key_length": "9",
      "rows_examined_per_scan": 24,
      "rows_produced_per_join": 24,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "16.04",
        "eval_cost": "2.40",
        "prefix_cost": "18.44",
        "data_read_per_join": "109K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`cscart_db`.`cscart_product_descriptions`.`product_id` in (18345,18346,18347,18348,18349,18350,19542,20113,20119,20120,21943,21992,21999,22000,22413,22414,22418,23717,23730,24175,24176,25619,25621,25969)) and (`cscart_db`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}