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 (
    1288, 1289, 1767, 1347, 665, 581, 299, 
    301, 1799, 1462, 1549, 1521, 1519, 1517, 
    1522, 1523, 1518, 1516, 1520, 30, 31, 
    1545, 1483, 409, 550, 840, 197, 68, 1180, 
    1205
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00133

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 (1288,1289,1767,1347,665,581,299,301,1799,1462,1549,1521,1519,1517,1522,1523,1518,1516,1520,30,31,1545,1483,409,550,840,197,68,1180,1205) and cscart_product_descriptions.lang_code = 'en'"
    }
  }
}

Result

product_id short_description full_description meta_keywords meta_description search_words promo_text unit_name
30
31
68
197
299
301
409
550
581
665
840
1180
1205
1288
1289
1347
1462
1483
1516
1517
1518
1519
1520
1521
1522
1523
1545
1549
1767
1799