SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '' 
    OR cscart_product_descriptions.short_description IS NULL, 
    cscart_product_descriptions.full_description, 
    ''
  ) AS full_description, 
  cscart_product_descriptions.meta_keywords, 
  cscart_product_descriptions.meta_description, 
  cscart_product_descriptions.search_words, 
  cscart_product_descriptions.promo_text, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (9783, 9786, 9788) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": ["PRIMARY", "product_id"],
      "key": "PRIMARY",
      "key_length": "9",
      "used_key_parts": ["product_id", "lang_code"],
      "rows": 3,
      "filtered": 100,
      "index_condition": "cscart_product_descriptions.product_id in (9783,9786,9788) and cscart_product_descriptions.lang_code = 'ru'"
    }
  }
}

Result

product_id short_description full_description meta_keywords meta_description search_words promo_text unit_name
9783 <p> Коллекция Фантазия </p><p><iframe width="100%" height="315" src="https://www.youtube.com/embed/aQE34Ct0KGU" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe></p>
9786 <p> Коллекция Фантазия </p><p><iframe width="100%" height="315" src="https://www.youtube.com/embed/aQE34Ct0KGU" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe></p>
9788 <p> Коллекция Фантазия </p><p><iframe width="100%" height="315" src="https://www.youtube.com/embed/aQE34Ct0KGU" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe></p>