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 (
    85896, 85897, 85902, 85884, 85903, 85885, 
    85899, 85890, 85898, 85891, 85905, 
    85887, 85904, 85886, 85893, 85895, 
    85892, 85901, 85883, 85889, 85879, 
    85880, 85874, 85875, 85881, 85876, 
    85878, 85873, 85877, 85872, 85914, 
    85915, 85919, 85946, 85947, 85912, 
    85945, 85926, 85923, 85928, 85921, 
    85943, 85944, 85942, 85937, 85938, 
    85936, 85934
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00050

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.63"
    },
    "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": "16.83",
        "eval_cost": "4.80",
        "prefix_cost": "21.63",
        "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 (85896,85897,85902,85884,85903,85885,85899,85890,85898,85891,85905,85887,85904,85886,85893,85895,85892,85901,85883,85889,85879,85880,85874,85875,85881,85876,85878,85873,85877,85872,85914,85915,85919,85946,85947,85912,85945,85926,85923,85928,85921,85943,85944,85942,85937,85938,85936,85934)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
85872 Nuie Deco Wall Hung 400mm Unit WC & Tap - Satin White
85873 Nuie Deco Wall Hung 400mm Unit WC & Tap - Satin Grey
85874 Nuie Deco Wall Hung 400mm Unit WC & Tap - Satin Anthracite
85875 Nuie Deco Wall Hung 400mm Unit WC & Tap - Satin Blue
85876 Nuie Deco Wall Hung 400mm Unit WC & Tap - Satin Green
85877 Nuie Deco Floor Standing 400mm Unit WC & Tap - Satin White
85878 Nuie Deco Floor Standing 400mm Unit WC & Tap - Satin Grey
85879 Nuie Deco Floor Standing 400mm Unit WC & Tap - Satin Anthracite
85880 Nuie Deco Floor Standing 400mm Unit WC & Tap - Satin Blue
85881 Nuie Deco Floor Standing 400mm Unit WC & Tap - Satin Green
85883 Hudson Reed Juno Wall Hung 440mm WC & Tap - Graphite Grey
85884 Hudson Reed Juno Wall Hung 440mm WC & Tap - Metallic Slate
85885 Hudson Reed Juno Wall Hung 440mm WC & Tap - Autumn Oak
85886 Hudson Reed Juno Wall Hung 440mm WC & Tap - Coastal Grey
85887 Hudson Reed Juno Wall Hung 440mm WC & Tap - Electric Blue
85889 Hudson Reed Juno Wall Hung 440mm WC & Tap - Graphite Grey
85890 Hudson Reed Juno Wall Hung 440mm WC & Tap - Metallic Slate
85891 Hudson Reed Juno Wall Hung 440mm WC & Tap - Autumn Oak
85892 Hudson Reed Juno Wall Hung 440mm WC & Tap - Coastal Grey
85893 Hudson Reed Juno Wall Hung 440mm WC & Tap - Electric Blue
85895 Hudson Reed Juno Floor Standing 440mm WC & Tap - Graphite Grey
85896 Hudson Reed Juno Floor Standing 440mm WC & Tap - Metallic Slate
85897 Hudson Reed Juno Floor Standing 440mm WC & Tap - Autumn Oak
85898 Hudson Reed Juno Floor Standing 440mm WC & Tap - Coastal Grey
85899 Hudson Reed Juno Floor Standing 440mm WC & Tap - Electric Blue
85901 Hudson Reed Juno Floor Standing 440mm WC & Tap - Graphite Grey
85902 Hudson Reed Juno Floor Standing 440mm WC & Tap - Metallic Slate
85903 Hudson Reed Juno Floor Standing 440mm WC & Tap - Autumn Oak
85904 Hudson Reed Juno Floor Standing 440mm WC & Tap - Coastal Grey
85905 Hudson Reed Juno Floor Standing 440mm WC & Tap - Electric Blue
85912 Nuie Merit Wall Hung 500mm Unit WC & Tap - Gloss White
85914 Nuie Merit Wall Hung 500mm Unit WC & Tap - Anthracite Woodgrain
85915 Nuie Merit Wall Hung 500mm Unit WC & Tap - Charcoal Black
85919 Nuie Merit Wall Hung 500mm Unit WC & Tap - Electric Blue
85921 Nuie Merit Slimline Wall Hung 500mm Unit WC & Tap - Gloss White
85923 Nuie Merit Slimline Wall Hung 500mm Unit WC & Tap - Anthracite Woodgrain
85926 Nuie Merit Slimline Wall Hung 500mm Unit WC & Tap - Gloss Grey
85928 Nuie Merit Slimline Wall Hung 500mm Unit WC & Tap - Electric Blue
85934 Nuie Core Wall Hung 500mm Unit Tap & WC - Satin Anthracite
85936 Nuie Core Wall Hung 600mm Unit Tap & WC - Satin White
85937 Nuie Core Wall Hung 600mm Unit Tap & WC - Satin Anthracite
85938 Nuie Core Wall Hung 600mm Unit Tap & WC - Satin Green
85942 Nuie Core Floor Standing 500mm Unit Tap & WC - Satin White
85943 Nuie Core Floor Standing 500mm Unit Tap & WC - Satin Anthracite
85944 Nuie Core Floor Standing 500mm Unit Tap & WC - Satin Green
85945 Nuie Core Floor Standing 600mm Unit Tap & WC - Satin White
85946 Nuie Core Floor Standing 600mm Unit Tap & WC - Satin Anthracite
85947 Nuie Core Floor Standing 600mm Unit Tap & WC - Satin Green