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 (
    1285, 1283, 1284, 1282, 1401, 1402, 1403, 
    1384, 727, 729, 726, 1583, 251, 237, 
    238, 373, 372, 339, 365, 236, 786, 381, 
    389, 1914, 1321, 1368, 1877, 1876, 1878, 
    1806, 1794, 1807, 1884, 1886, 1889, 
    1890, 1881, 1879, 1880, 1882, 1888, 
    1871, 1887, 715, 714, 1485, 1915, 345
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00170

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": 48,
      "filtered": 100,
      "index_condition": "cscart_product_descriptions.product_id in (1285,1283,1284,1282,1401,1402,1403,1384,727,729,726,1583,251,237,238,373,372,339,365,236,786,381,389,1914,1321,1368,1877,1876,1878,1806,1794,1807,1884,1886,1889,1890,1881,1879,1880,1882,1888,1871,1887,715,714,1485,1915,345) and cscart_product_descriptions.lang_code = 'en'"
    }
  }
}

Result

product_id short_description full_description meta_keywords meta_description search_words promo_text unit_name
236
237
238
251
339
345
365
372
373
381
389
714
715
726
727
729
786
1282
1283
1284
1285
1321
1368
1384
1401
1402
1403
1485
1583
1794
1806
1807
1871
1876
1877
1878
1879
1880
1881
1882
1884
1886
1887
1888
1889
1890
1914
1915