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 (
    34283, 39054, 63926, 65693, 9464, 36454, 
    68345, 29768, 31344, 68351, 68585, 
    39124, 68969, 68588, 58579, 68587, 
    68610, 18067, 66418, 66479, 67724, 
    69020, 70258, 18063
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00099

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.17"
    },
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "product_id",
        "idx_product_desc_lang",
        "idx_product_name_search",
        "idx_product_desc_sort"
      ],
      "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": "18.77",
        "eval_cost": "2.40",
        "prefix_cost": "21.17",
        "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 (34283,39054,63926,65693,9464,36454,68345,29768,31344,68351,68585,39124,68969,68588,58579,68587,68610,18067,66418,66479,67724,69020,70258,18063)) and (`cscart_db`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}