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 (
    88066, 88075, 88082, 87958, 89982, 89983, 
    89984, 88046, 88045, 87987, 87997, 
    88026, 88047, 88048, 88050, 88051, 
    87937, 87950, 87952, 88004, 87948, 
    88029, 93794, 94496, 94499, 94501, 
    94515, 94581, 94843, 94850, 94852, 
    95309, 95316, 95376, 95762, 95778, 
    95779, 95823, 96119, 96508, 96530, 
    96570, 96572, 97620, 97623, 97625, 
    97639, 97705, 99111, 99122, 99124, 
    99126, 99129, 99163, 99172, 99178, 
    99184, 99204, 99207, 99223, 99224, 
    99225, 99226, 99228, 99229, 99244, 
    99253, 99260, 99271, 99280, 99281, 
    100388, 100389, 100432, 100671, 100672, 
    100673
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00170

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "34.68"
    },
    "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": 77,
      "rows_produced_per_join": 77,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "26.99",
        "eval_cost": "7.70",
        "prefix_cost": "34.69",
        "data_read_per_join": "293K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (88066,88075,88082,87958,89982,89983,89984,88046,88045,87987,87997,88026,88047,88048,88050,88051,87937,87950,87952,88004,87948,88029,93794,94496,94499,94501,94515,94581,94843,94850,94852,95309,95316,95376,95762,95778,95779,95823,96119,96508,96530,96570,96572,97620,97623,97625,97639,97705,99111,99122,99124,99126,99129,99163,99172,99178,99184,99204,99207,99223,99224,99225,99226,99228,99229,99244,99253,99260,99271,99280,99281,100388,100389,100432,100671,100672,100673)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
87937 Hudson Reed Chancery Cistern
87948 nuie Provost Short Projection Cistern
87950 nuie Lawton Curved Cistern
87952 nuie Lawton New Cistern
87958 nuie Ambrose Close Coupled Short Projection Cistern & Fittings
87987 nuie Bliss Square Cistern & Fittings
87997 nuie Provost Cistern
88004 nuie Harmony Cistern & Fittings
88026 nuie Ivo Close Coupled Cistern
88029 nuie Legend Cistern Including Chrome Handle
88045 nuie Carlton Low Level Cistern Ceramic Lever Fittings
88046 Old London Richmond Low Level Cistern B Ceramic Lever Fittings
88047 nuie Carlton High Level Cistern (Including Fittings)
88048 Old London Richmond High Level Cistern B (Including Fittings)
88050 nuie Carlton Toilet Cistern with Chrome Lever & Fitting
88051 Old London Richmond Toilet Cistern B Ceramic Lever Fittings
88066 Hudson Reed Maya Cistern C/W Fittings
88075 Hudson Reed Luna Back to Wall Close Coupled Cistern
88082 Hudson Reed Arlo Compact Close Coupled Cistern
89982 BC Designs Victrion Close Coupled Cistern & Fittings - White
89983 BC Designs Victrion low/Medium Level Cistern - White
89984 BC Designs Victrion High Level Cistern - White
93794
94496
94499
94501
94515
94581
94843
94850
94852
95309
95316
95376
95762
95778
95779
95823
96119
96508
96530
96570
96572
97620
97623
97625
97639
97705
99111
99122
99124
99126
99129
99163
99172
99178
99184
99204
99207
99223
99224
99225
99226
99228
99229
99244
99253
99260
99271
99280
99281
100388
100389
100432
100671
100672
100673