SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '', 
    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 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    1248, 1256, 1253, 1249, 1255, 1252, 1257, 
    1250, 1254, 1251
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00049

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": 10,
      "filtered": 100,
      "index_condition": "cscart_product_descriptions.product_id in (1248,1256,1253,1249,1255,1252,1257,1250,1254,1251) and cscart_product_descriptions.lang_code = 'ru'"
    }
  }
}

Result

product_id short_description full_description meta_keywords meta_description search_words promo_text
1248 <p><iframe src="https://www.youtube.com/embed/8PS9C6U2XCw" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen="" width="100%" height="415" frameborder="0"></iframe></p>
1249 <p><iframe width="100%" height="415" src="https://www.youtube.com/embed/8PS9C6U2XCw" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe></p>
1250 <p><iframe src="https://www.youtube.com/embed/8PS9C6U2XCw" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen="" width="100%" height="415" frameborder="0"></iframe></p>
1251 <p><iframe width="100%" height="415" src="https://www.youtube.com/embed/8PS9C6U2XCw" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe></p>
1252 <p><iframe width="100%" height="415" src="https://www.youtube.com/embed/8PS9C6U2XCw" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe></p>
1253 <p><iframe width="100%" height="415" src="https://www.youtube.com/embed/8PS9C6U2XCw" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe></p>
1254 <p><iframe width="100%" height="415" src="https://www.youtube.com/embed/8PS9C6U2XCw" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe></p>
1255 <p><iframe width="100%" height="415" src="https://www.youtube.com/embed/8PS9C6U2XCw" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe></p>
1256 <p><iframe width="100%" height="415" src="https://www.youtube.com/embed/8PS9C6U2XCw" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe></p>
1257 <p><iframe width="100%" height="415" src="https://www.youtube.com/embed/8PS9C6U2XCw" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe></p>