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 (
    1947, 1458, 1460, 1464, 1455, 1382, 1385, 
    1383, 1386, 25, 1758, 1757, 1734, 1254, 
    1684, 1379, 1378, 1792, 1791, 1793, 
    1789, 1716, 1714, 1715, 1720, 1719, 
    1722, 1713, 1718, 1717, 1867, 1721, 
    1685, 1207, 1210, 1203, 1389, 1188, 
    1190, 1209, 1186, 1852, 1456, 1457, 
    1045, 1046, 1187, 1577, 1194, 368, 1253
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00157

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": 51,
      "filtered": 100,
      "index_condition": "cscart_product_descriptions.product_id in (1947,1458,1460,1464,1455,1382,1385,1383,1386,25,1758,1757,1734,1254,1684,1379,1378,1792,1791,1793,1789,1716,1714,1715,1720,1719,1722,1713,1718,1717,1867,1721,1685,1207,1210,1203,1389,1188,1190,1209,1186,1852,1456,1457,1045,1046,1187,1577,1194,368,1253) and cscart_product_descriptions.lang_code = 'en'"
    }
  }
}

Result

product_id short_description full_description meta_keywords meta_description search_words promo_text unit_name
25
368
1045
1046
1186
1187
1188
1190
1194
1203
1207
1209
1210
1253
1254
1378
1379
1382
1383
1385
1386
1389
1455
1456
1457
1458
1460
1464
1577
1684
1685
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1734
1757
1758
1789
1791
1792
1793
1852
1867
1947