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 (
    29989, 69055, 69077, 26800, 69059, 69097, 
    69076, 29990, 69060, 69062, 69066, 
    69064, 26799, 28654, 69056, 69074, 
    69063, 69091, 26051, 19109, 21338, 
    69065, 69069, 69083
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00080

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.37"
    },
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "product_id",
        "idx_product_desc_lang",
        "idx_product_name_search",
        "idx_product_desc_sort"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id",
        "lang_code"
      ],
      "key_length": "9",
      "rows_examined_per_scan": 24,
      "rows_produced_per_join": 24,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "18.97",
        "eval_cost": "2.40",
        "prefix_cost": "21.37",
        "data_read_per_join": "109K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`cscart_db`.`cscart_product_descriptions`.`product_id` in (29989,69055,69077,26800,69059,69097,69076,29990,69060,69062,69066,69064,26799,28654,69056,69074,69063,69091,26051,19109,21338,69065,69069,69083)) and (`cscart_db`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}