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 (
    97177, 97178, 97179, 97180, 97181, 97182, 
    97183, 97184, 97185, 97186, 97187, 
    97188, 97189, 97190, 97191, 97192, 
    97193, 97194, 97195, 97196, 97197, 
    97198, 97199, 97200, 97201, 97202, 
    97203, 97204, 97205, 97206
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00040

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 (97177,97178,97179,97180,97181,97182,97183,97184,97185,97186,97187,97188,97189,97190,97191,97192,97193,97194,97195,97196,97197,97198,97199,97200,97201,97202,97203,97204,97205,97206)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
97177
97178
97179
97180
97181
97182
97183
97184
97185
97186
97187
97188
97189
97190
97191
97192
97193
97194
97195
97196
97197
97198
97199
97200
97201
97202
97203
97204
97205
97206