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 (
    89976, 89977, 89978, 89979, 89980, 89981, 
    88069, 88068, 88067, 88083, 87938, 
    87941, 87988, 88052, 88053, 88054, 
    87990, 87961, 87959, 87998, 88000, 
    88031, 87945, 87942, 87964, 88018, 
    88021, 88006, 88013, 88015, 87972, 
    87944, 88154, 94484, 94486, 94487, 
    94488, 94489, 94490, 94491, 94493, 
    94494, 94505, 94506, 94507, 94509, 
    94511, 94512, 94513, 94516, 94517, 
    94518, 94519, 94520, 94521, 94522, 
    94523, 94524, 94525, 94526, 94527, 
    94528, 94529, 94530, 94531, 94532, 
    94533, 94534, 94535, 94536, 94537, 
    94538, 94539, 94540, 94541, 94542, 
    94543, 94544, 94545, 94546, 94547, 
    94548, 94549, 94550, 94551, 94552, 
    94553, 94554, 94555, 94556, 94557, 
    94573, 94575, 94576, 94577, 94578
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00174

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 (89976,89977,89978,89979,89980,89981,88069,88068,88067,88083,87938,87941,87988,88052,88053,88054,87990,87961,87959,87998,88000,88031,87945,87942,87964,88018,88021,88006,88013,88015,87972,87944,88154,94484,94486,94487,94488,94489,94490,94491,94493,94494,94505,94506,94507,94509,94511,94512,94513,94516,94517,94518,94519,94520,94521,94522,94523,94524,94525,94526,94527,94528,94529,94530,94531,94532,94533,94534,94535,94536,94537,94538,94539,94540,94541,94542,94543,94544,94545,94546,94547,94548,94549,94550,94551,94552,94553,94554,94555,94556,94557,94573,94575,94576,94577,94578)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
87938 Hudson Reed Chancery Large Basin 1 Tap Hole
87941 Hudson Reed Chancery Large Basin 2 Tap Hole
87942 Hudson Reed Chancery Small Cloakroom Basin 2 Tap Hole
87944 nuie Asselby Small Cloakroom Basin 1 Tap Hole
87945 nuie Asselby 600mm Medium Basin 1 Tap Hole
87959 nuie Ambrose 450mm Basin 1 Tap Hole
87961 nuie Ambrose 500mm Basin 1 Tap Hole
87964 Nuie 550mm Basin 1 Tap Hole
87972 Nuie 545mm Basin 1 Tap Hole
87988 nuie Bliss Square 600mm Basin 1 Tap Hole
87990 nuie Bliss Square 520mm Basin 1 Tap Hole
87998 nuie Provost 420mm Small Basin 1 Tap Hole
88000 nuie Provost Medium 520mm Basin 1 Tap Hole
88006 nuie Harmony 500mm Basin 1 Tap Hole
88013 nuie Melbourne Large Basin 1 Tap Hole
88015 nuie Melbourne Large Basin 2 Tap Hole
88018 <p>nuie Ivo Large Basin 1 Tap Hole</p>
88021 nuie Ivo 550 Basin 2 Tap Hole
88031 nuie Legend Large Basin 2 Tap Hole
88052 Hudson Reed Richmond Wall Hung 2 Tap Hole Basin 595mm
88053 Hudson Reed Richmond Wall Hung 1 Tap Hole Basin 595mm
88054 Hudson Reed Richmond Wall Hung 3 Tap Hole Basin 595mm
88067 Hudson Reed Maya 550mm Basin 1 Tap Hole
88068 Hudson Reed Maya 650mm Basin 1 Tap Hole
88069 Hudson Reed Maya 850mm Basin 1 Tap Hole
88083 Hudson Reed Arlo 550mm 1 Tap Hole Basin
88154 nuie Lawton 560mm Basin 1 Tap Hole
89976 BC Designs Victrion 640mm Basin 1TH - White
89977 BC Designs Victrion 640mm Basin 2TH - White
89978 BC Designs Victrion 640mm Basin 3TH - White
89979 BC Designs Victrion 540mm Basin 1TH - White
89980 BC Designs Victrion Square Ceramic Basin 2 Tap Hole - 540mm - White
89981 BC Designs Victrion Square Ceramic Basin 3 Tap Hole - 540mm - White
94484
94486
94487
94488
94489
94490
94491
94493
94494
94505
94506
94507
94509
94511
94512
94513
94516
94517
94518
94519
94520
94521
94522
94523
94524
94525
94526
94527
94528
94529
94530
94531
94532
94533
94534
94535
94536
94537
94538
94539
94540
94541
94542
94543
94544
94545
94546
94547
94548
94549
94550
94551
94552
94553
94554
94555
94556
94557
94573
94575
94576
94577
94578