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 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    2017, 833, 41290, 44379, 22800, 35221, 
    28434, 5644, 1674, 1394, 26911, 1684, 
    35214, 924, 3498, 1798, 1518, 36525, 
    1547, 46588, 710, 1680, 22796, 46721, 
    32191, 1691, 27285, 5804, 5655, 37944, 
    3504, 4875
  ) 
  AND cscart_product_descriptions.lang_code = 'vi'

Query time 0.04600

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_product_descriptions",
          "access_type": "range",
          "possible_keys": ["PRIMARY", "product_id"],
          "key": "PRIMARY",
          "key_length": "11",
          "used_key_parts": ["product_id", "lang_code"],
          "rows": 32,
          "filtered": 100,
          "index_condition": "cscart_product_descriptions.product_id in (2017,833,41290,44379,22800,35221,28434,5644,1674,1394,26911,1684,35214,924,3498,1798,1518,36525,1547,46588,710,1680,22796,46721,32191,1691,27285,5804,5655,37944,3504,4875) and cscart_product_descriptions.lang_code = 'vi'"
        }
      }
    ]
  }
}