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 (
    98065, 98066, 98067, 98068, 98069, 98070, 
    98071, 98072, 98073, 98074, 98075, 
    98076, 98077, 98078, 98079, 98080, 
    98081, 98082, 98083, 98523, 98524, 
    98525, 98526, 98527
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00073

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "12.97"
    },
    "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": 24,
      "rows_produced_per_join": 24,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "10.57",
        "eval_cost": "2.40",
        "prefix_cost": "12.97",
        "data_read_per_join": "91K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (98065,98066,98067,98068,98069,98070,98071,98072,98073,98074,98075,98076,98077,98078,98079,98080,98081,98082,98083,98523,98524,98525,98526,98527)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
98065
98066
98067
98068
98069
98070
98071
98072
98073
98074
98075
98076
98077
98078
98079
98080
98081
98082
98083
98523
98524
98525
98526
98527