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 (
    101002, 101003, 101004, 101005, 101006, 
    101007, 101008, 101009, 101010, 101093, 
    101094, 101095, 101096, 101097, 101098, 
    101099, 101100, 101101, 101958, 101959, 
    101960, 101961, 101962
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "10.37"
    },
    "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": 23,
      "rows_produced_per_join": 23,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "8.07",
        "eval_cost": "2.30",
        "prefix_cost": "10.37",
        "data_read_per_join": "87K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (101002,101003,101004,101005,101006,101007,101008,101009,101010,101093,101094,101095,101096,101097,101098,101099,101100,101101,101958,101959,101960,101961,101962)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}