SELECT 
  cscart_ult_product_descriptions.product_id, 
  cscart_ult_product_descriptions.short_description, 
  IF(
    cscart_ult_product_descriptions.short_description = "", 
    cscart_ult_product_descriptions.full_description, 
    ""
  ) AS full_description, 
  cscart_ult_product_descriptions.meta_keywords, 
  cscart_ult_product_descriptions.meta_description, 
  cscart_ult_product_descriptions.search_words, 
  cscart_ult_product_descriptions.promo_text 
FROM 
  cscart_ult_product_descriptions 
WHERE 
  cscart_ult_product_descriptions.product_id IN (
    8418, 8415, 8417, 8403, 8409, 8396, 8399, 
    8416, 8404, 8398, 8420, 8394, 8419, 
    8401, 8400, 8402, 8412, 8407, 8393, 
    8411, 8408, 8406, 8405
  ) 
  AND cscart_ult_product_descriptions.company_id = 1 
  AND cscart_ult_product_descriptions.lang_code = 'ru'

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "0.35"
    },
    "table": {
      "table_name": "cscart_ult_product_descriptions",
      "access_type": "ref",
      "possible_keys": [
        "PRIMARY",
        "product_id",
        "company_id"
      ],
      "key": "company_id",
      "used_key_parts": [
        "company_id"
      ],
      "key_length": "4",
      "ref": [
        "const"
      ],
      "rows_examined_per_scan": 1,
      "rows_produced_per_join": 0,
      "filtered": "5.00",
      "cost_info": {
        "read_cost": "0.25",
        "eval_cost": "0.01",
        "prefix_cost": "0.35",
        "data_read_per_join": "195"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "company_id",
        "short_description",
        "full_description",
        "meta_keywords",
        "meta_description",
        "search_words",
        "promo_text"
      ],
      "attached_condition": "((`primapearl_r_new`.`cscart_ult_product_descriptions`.`product_id` in (8418,8415,8417,8403,8409,8396,8399,8416,8404,8398,8420,8394,8419,8401,8400,8402,8412,8407,8393,8411,8408,8406,8405)) and (`primapearl_r_new`.`cscart_ult_product_descriptions`.`lang_code` = 'ru'))"
    }
  }
}