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 (
    82885, 82887, 82958, 82960, 83332, 83334, 
    83342, 83344, 85350, 83026, 83027, 
    90862, 90863, 90941, 90942, 82809, 
    82882, 82955, 83329, 83339, 85094, 
    85095, 83549, 83554, 86491, 86767, 
    85305, 85402, 85453, 85504
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00090

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "13.52"
    },
    "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": 30,
      "rows_produced_per_join": 30,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "10.52",
        "eval_cost": "3.00",
        "prefix_cost": "13.52",
        "data_read_per_join": "114K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (82885,82887,82958,82960,83332,83334,83342,83344,85350,83026,83027,90862,90863,90941,90942,82809,82882,82955,83329,83339,85094,85095,83549,83554,86491,86767,85305,85402,85453,85504)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}