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 (
    1972, 2514, 2695, 44424, 36329, 48769, 
    37304, 38143, 27357, 2932, 27358, 40824, 
    2505, 33177, 47018, 49306, 3764, 3774, 
    27360, 33214, 4238, 2926, 5411, 3585, 
    382, 2136, 2502, 2961, 2132, 38558, 
    3168, 3663
  ) 
  AND cscart_product_descriptions.lang_code = 'vi'

Query time 0.01112

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 (1972,2514,2695,44424,36329,48769,37304,38143,27357,2932,27358,40824,2505,33177,47018,49306,3764,3774,27360,33214,4238,2926,5411,3585,382,2136,2502,2961,2132,38558,3168,3663) and cscart_product_descriptions.lang_code = 'vi'"
        }
      }
    ]
  }
}