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 (
    97791, 97792, 97793, 97794, 97875, 97876, 
    97877, 97878, 97879, 97880, 97881, 
    97882, 97886, 97888, 98001, 98002, 
    98003, 98004, 98005, 98006, 98007, 
    98008, 98009, 98010, 98011, 98012, 
    98013, 98014, 98015, 98016, 98017, 
    98018, 98019, 98020, 98021, 98022, 
    98023, 98176, 98177, 98178, 98179, 
    98180, 98181, 98182, 98183, 98184, 
    98185, 98186
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00094

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.63"
    },
    "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": 48,
      "rows_produced_per_join": 48,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "16.83",
        "eval_cost": "4.80",
        "prefix_cost": "21.63",
        "data_read_per_join": "183K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (97791,97792,97793,97794,97875,97876,97877,97878,97879,97880,97881,97882,97886,97888,98001,98002,98003,98004,98005,98006,98007,98008,98009,98010,98011,98012,98013,98014,98015,98016,98017,98018,98019,98020,98021,98022,98023,98176,98177,98178,98179,98180,98181,98182,98183,98184,98185,98186)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
97791
97792
97793
97794
97875
97876
97877
97878
97879
97880
97881
97882
97886
97888
98001
98002
98003
98004
98005
98006
98007
98008
98009
98010
98011
98012
98013
98014
98015
98016
98017
98018
98019
98020
98021
98022
98023
98176
98177
98178
98179
98180
98181
98182
98183
98184
98185
98186