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 (
    83007, 83290, 83292, 83297, 83299, 84806, 
    84807, 84824, 84825, 84836, 84837, 
    91096, 91182, 91237, 83059, 83063, 
    83064, 83608, 83616, 83617, 85339, 
    89806, 89858, 89930, 90895, 90899, 
    90900, 90974, 90978, 90979
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00048

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 (83007,83290,83292,83297,83299,84806,84807,84824,84825,84836,84837,91096,91182,91237,83059,83063,83064,83608,83616,83617,85339,89806,89858,89930,90895,90899,90900,90974,90978,90979)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}