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 (
    99315, 99316, 99317, 99318, 99330, 99331, 
    99332, 99347, 99349, 99351, 99353, 
    99355, 99413, 99414, 99415, 99416, 
    99417, 99418, 99419, 99420, 99421, 
    99441, 99442, 99448, 99449, 99450, 
    99451, 99459, 99460, 99461, 99462, 
    99464, 99465, 99470, 99471, 99472, 
    99473, 99478, 99479, 99480, 99481, 
    99487, 99488, 99489, 99490, 99558, 
    99559, 99560, 99566, 99567, 99568, 
    99569, 99577, 99578, 99579, 99648, 
    99649, 99650, 99651, 99652, 100139, 
    100140, 100141, 100142, 100157, 100158, 
    100159, 100160, 100212, 100213, 100214, 
    100215, 100216, 100649, 100650, 100651, 
    100652, 100653, 101038, 101039, 101040, 
    101041, 101042, 101043, 101044, 101045, 
    101046, 101134, 101135, 101136, 101137, 
    101138, 101139, 101140, 101141, 101142
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00095

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "43.24"
    },
    "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": 96,
      "rows_produced_per_join": 96,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "33.64",
        "eval_cost": "9.60",
        "prefix_cost": "43.24",
        "data_read_per_join": "366K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (99315,99316,99317,99318,99330,99331,99332,99347,99349,99351,99353,99355,99413,99414,99415,99416,99417,99418,99419,99420,99421,99441,99442,99448,99449,99450,99451,99459,99460,99461,99462,99464,99465,99470,99471,99472,99473,99478,99479,99480,99481,99487,99488,99489,99490,99558,99559,99560,99566,99567,99568,99569,99577,99578,99579,99648,99649,99650,99651,99652,100139,100140,100141,100142,100157,100158,100159,100160,100212,100213,100214,100215,100216,100649,100650,100651,100652,100653,101038,101039,101040,101041,101042,101043,101044,101045,101046,101134,101135,101136,101137,101138,101139,101140,101141,101142)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
99315
99316
99317
99318
99330
99331
99332
99347
99349
99351
99353
99355
99413
99414
99415
99416
99417
99418
99419
99420
99421
99441
99442
99448
99449
99450
99451
99459
99460
99461
99462
99464
99465
99470
99471
99472
99473
99478
99479
99480
99481
99487
99488
99489
99490
99558
99559
99560
99566
99567
99568
99569
99577
99578
99579
99648
99649
99650
99651
99652
100139
100140
100141
100142
100157
100158
100159
100160
100212
100213
100214
100215
100216
100649
100650
100651
100652
100653
101038
101039
101040
101041
101042
101043
101044
101045
101046
101134
101135
101136
101137
101138
101139
101140
101141
101142