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 (
    97076, 97077, 97078, 97079, 97080, 97081, 
    97082, 97084, 97085, 97086, 97087, 
    97088, 97089, 97090, 97091, 97092, 
    97093, 97094, 97095, 97096, 97097, 
    97098, 97099, 97100, 97101, 97102, 
    97103, 97104, 97105, 97106
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00043

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 (97076,97077,97078,97079,97080,97081,97082,97084,97085,97086,97087,97088,97089,97090,97091,97092,97093,97094,97095,97096,97097,97098,97099,97100,97101,97102,97103,97104,97105,97106)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
97076
97077
97078
97079
97080
97081
97082
97084
97085
97086
97087
97088
97089
97090
97091
97092
97093
97094
97095
97096
97097
97098
97099
97100
97101
97102
97103
97104
97105
97106