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 (
    692, 1189, 845, 765, 598, 1024, 1416, 
    1432, 1410, 558, 557, 556, 1421, 1406, 
    1422, 1413, 753, 566, 1021, 536, 686, 
    519, 764, 1226, 1419, 1447, 613, 545, 
    685, 1012
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00125

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": 30,
      "filtered": 100,
      "index_condition": "cscart_product_descriptions.product_id in (692,1189,845,765,598,1024,1416,1432,1410,558,557,556,1421,1406,1422,1413,753,566,1021,536,686,519,764,1226,1419,1447,613,545,685,1012) and cscart_product_descriptions.lang_code = 'en'"
    }
  }
}

Result

product_id short_description full_description meta_keywords meta_description search_words promo_text unit_name
519
536
545
556
557
558
566
598
613
685
686
692
753
764
765
845
1012
1021
1024
1189
1226
1406
1410
1413
1416
1419
1421
1422
1432
1447