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 (
    95149, 95150, 95151, 95159, 95161, 95162, 
    95163, 95164, 95246, 95247, 95248, 
    95249, 95250, 95251, 95252, 95253, 
    95254, 95255, 95256, 95257, 95258, 
    95259, 95260, 95261, 95262, 95263, 
    95264, 95265, 95266, 95267
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00111

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 (95149,95150,95151,95159,95161,95162,95163,95164,95246,95247,95248,95249,95250,95251,95252,95253,95254,95255,95256,95257,95258,95259,95260,95261,95262,95263,95264,95265,95266,95267)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
95149
95150
95151
95159
95161
95162
95163
95164
95246
95247
95248
95249
95250
95251
95252
95253
95254
95255
95256
95257
95258
95259
95260
95261
95262
95263
95264
95265
95266
95267