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 (
    95487, 95494, 95495, 95496, 95505, 95506, 
    95509, 95510, 96182, 96183, 96184, 
    96185, 96785, 96786, 96817, 96818, 
    96819, 96820, 96821, 96822, 96823, 
    96824, 96825, 96893, 96894, 96895, 
    96896, 96897, 96898, 96899, 96900, 
    96901, 96902, 96903, 96904, 96905, 
    96906, 96907, 96908, 96909, 96910, 
    96911, 96912, 96913, 96914, 96915, 
    96916, 96969
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00086

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.62"
    },
    "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": "16.82",
        "eval_cost": "4.80",
        "prefix_cost": "21.62",
        "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 (95487,95494,95495,95496,95505,95506,95509,95510,96182,96183,96184,96185,96785,96786,96817,96818,96819,96820,96821,96822,96823,96824,96825,96893,96894,96895,96896,96897,96898,96899,96900,96901,96902,96903,96904,96905,96906,96907,96908,96909,96910,96911,96912,96913,96914,96915,96916,96969)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
95487
95494
95495
95496
95505
95506
95509
95510
96182
96183
96184
96185
96785
96786
96817
96818
96819
96820
96821
96822
96823
96824
96825
96893
96894
96895
96896
96897
96898
96899
96900
96901
96902
96903
96904
96905
96906
96907
96908
96909
96910
96911
96912
96913
96914
96915
96916
96969