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 (
    97117, 97118, 97119, 97120, 97121, 97122, 
    97123, 97124, 97125, 97126, 97127, 
    97128, 97129, 97130, 97131, 97132, 
    97133, 97134, 97135, 97136, 97137, 
    97138, 97139, 97140, 97141, 97142, 
    97143, 97144, 97145, 97146
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00076

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 (97117,97118,97119,97120,97121,97122,97123,97124,97125,97126,97127,97128,97129,97130,97131,97132,97133,97134,97135,97136,97137,97138,97139,97140,97141,97142,97143,97144,97145,97146)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
97117
97118
97119
97120
97121
97122
97123
97124
97125
97126
97127
97128
97129
97130
97131
97132
97133
97134
97135
97136
97137
97138
97139
97140
97141
97142
97143
97144
97145
97146