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 (
    1768, 1710, 1954, 1953, 1730, 1686, 1593, 
    1594, 1616, 1773, 1701, 1584, 1585, 
    1868, 1579, 1956, 1495, 1739, 1740, 
    1912, 1913, 1650, 56, 1836
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00113

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": 24,
      "filtered": 100,
      "index_condition": "cscart_product_descriptions.product_id in (1768,1710,1954,1953,1730,1686,1593,1594,1616,1773,1701,1584,1585,1868,1579,1956,1495,1739,1740,1912,1913,1650,56,1836) and cscart_product_descriptions.lang_code = 'en'"
    }
  }
}

Result

product_id short_description full_description meta_keywords meta_description search_words promo_text unit_name
56
1495
1579
1584
1585
1593
1594
1616
1650
1686
1701
1710
1730
1739
1740
1768
1773
1836
1868
1912
1913
1953
1954
1956