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 (
    1761, 1733, 1759, 1712, 1682, 1758, 1757, 
    1734, 1756, 1755, 1754, 1753, 1689, 
    1752, 1751, 1748, 1649, 1743, 1750, 
    1749, 1731, 1683, 1747, 1746
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00097

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 (1761,1733,1759,1712,1682,1758,1757,1734,1756,1755,1754,1753,1689,1752,1751,1748,1649,1743,1750,1749,1731,1683,1747,1746) and cscart_product_descriptions.lang_code = 'en'"
    }
  }
}

Result

product_id short_description full_description meta_keywords meta_description search_words promo_text unit_name
1649
1682
1683
1689
1712
1731
1733
1734
1743
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1761