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 (
    101923, 101924, 101925, 101926, 101927, 
    101932, 101933, 101934, 101935, 101936, 
    101937, 101938, 101939, 101940, 101941, 
    101942, 101943, 101944, 101945, 101946, 
    101947, 101948, 101949, 101950, 101951
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00059

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "11.27"
    },
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "product_id"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id",
        "lang_code"
      ],
      "key_length": "9",
      "rows_examined_per_scan": 25,
      "rows_produced_per_join": 25,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "8.77",
        "eval_cost": "2.50",
        "prefix_cost": "11.27",
        "data_read_per_join": "95K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (101923,101924,101925,101926,101927,101932,101933,101934,101935,101936,101937,101938,101939,101940,101941,101942,101943,101944,101945,101946,101947,101948,101949,101950,101951)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}