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 (
    87192, 87209, 87226, 87231, 84642, 84510, 
    84576, 84624, 84558, 85015, 85021, 
    85027, 85033, 84312, 84643, 88780, 
    84625, 84511, 84577, 84294, 88778, 
    88779, 89212, 89225, 89238, 88686, 
    88733, 84493, 84559, 88177, 88225, 
    88777, 88684, 88685, 88731, 88732, 
    87454, 88683, 88730, 89038, 85723, 
    85740, 85750, 85760, 88504, 91446, 
    91460, 88201
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00099

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 (87192,87209,87226,87231,84642,84510,84576,84624,84558,85015,85021,85027,85033,84312,84643,88780,84625,84511,84577,84294,88778,88779,89212,89225,89238,88686,88733,84493,84559,88177,88225,88777,88684,88685,88731,88732,87454,88683,88730,89038,85723,85740,85750,85760,88504,91446,91460,88201)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
84294 Hudson Reed Fusion Floor Standing WC Unit & Top Compact 500mm - Gloss White
84312 Hudson Reed Fusion Floor Standing WC Unit & Polymarble Top Compact 600mm - Gloss White
84493 Hudson Reed Fusion Floor Standing WC Unit with Coordinating Top Compact 500mm - Anthracite Woodgrain
84510 Hudson Reed Fusion Floor Standing WC Unit & Polymarble Top Compact 600mm - Anthracite Woodgrain
84511 Hudson Reed Fusion Floor Standing WC Unit with Coordinating Top Compact 600mm - Anthracite Woodgrain
84558 Hudson Reed Fusion Floor Standing WC Unit & Top Compact 500mm - Hacienda Black
84559 Hudson Reed Fusion Floor Standing WC Unit with Coordinating Top Compact 500mm - Hacienda Black
84576 Hudson Reed Fusion Floor Standing WC Unit & Polymarble Top Compact 600mm - Hacienda Black
84577 Hudson Reed Fusion Floor Standing WC Unit with Coordinating Top Compact 600mm - Hacienda Black
84624 Hudson Reed Fusion Floor Standing WC Unit & Top Compact 500mm - Gloss Grey
84625 Hudson Reed Fusion Floor Standing WC Unit with Coordinating Top Compact 500mm - Gloss Grey
84642 Hudson Reed Fusion Floor Standing WC Unit & Polymarble Top Compact 600mm - Gloss Grey
84643 Hudson Reed Fusion Floor Standing WC Unit with Coordinating Top Compact 600mm - Gloss Grey
85015 Hudson Reed Solar Floor Standing WC Unit 550mm - Pure White
85021 Hudson Reed Solar Floor Standing WC Unit 550mm - Cool Grey
85027 Hudson Reed Solar Floor Standing WC Unit 550mm - Indigo Blue
85033 Hudson Reed Solar 550mm Floor Standing WC Unit - Fern Green
85723 Hudson Reed Fluted 500mm Floor Standing WC Unit - Satin Anthracite
85740 Hudson Reed Fluted 500mm Floor Standing WC Unit - Satin Grey
85750 Hudson Reed Fluted 500mm Floor Standing WC Unit - Satin Blue
85760 Hudson Reed Fluted 500mm Floor Standing WC Unit - Satin Green
87192 Old London Floor Standing WC Unit 550mm - Storm Grey
87209 Old London Floor Standing WC Unit 550mm - Twilight Blue
87226 Old London Floor Standing WC Unit 550mm - Timeless Sand
87231 Old London Floor Standing WC Unit 550mm - Hunter Green
87454 nuie Athena Floor Standing WC Unit 500mm - Gloss Grey
88177 Hudson Reed Juno 550mm WC Unit - Autumn Oak
88201 Hudson Reed Juno 550mm WC Unit - Graphite Grey
88225 Hudson Reed Havana Floor Standing Concealed Cistern WC Toilet Unit, 500mm - Metallic Slate
88504 nuie Arno Compact 500mm Floor Standing WC Unit - Satin Green
88683 Hudson Reed Fusion Fitted Floor Standing WC Unit Compact 500mm - Anthracite Woodgrain
88684 Hudson Reed Fusion Fitted Floor Standing WC Unit 500mm - Anthracite Woodgrain
88685 Hudson Reed Fusion Fitted Floor Standing WC Unit Compact 600mm - Anthracite Woodgrain
88686 Hudson Reed Fusion Fitted Floor Standing WC Unit 600mm - Anthracite Woodgrain
88730 Hudson Reed Fusion Fitted Floor Standing WC Unit Compact 500mm - Hacienda Black
88731 Hudson Reed Fusion Fitted Floor Standing WC Unit 500mm - Hacienda Black
88732 Hudson Reed Fusion Fitted Floor Standing WC Unit Compact 600mm - Hacienda Black
88733 Hudson Reed Fusion Fitted Floor Standing WC Unit 600mm - Hacienda Black
88777 Hudson Reed Fusion Fitted Floor Standing WC Unit Compact 500mm - Gloss Grey
88778 Hudson Reed Fusion Fitted Floor Standing WC Unit 500mm - Gloss Grey
88779 Hudson Reed Fusion Fitted Floor Standing WC Unit Compact 600mm - Gloss Grey
88780 Hudson Reed Fusion Fitted Floor Standing WC Unit 600mm - Gloss Grey
89038 nuie Mayford Floor Standing WC Unit 600mm - Gloss White
89212 Hudson Reed Sarenna Floor Standing WC Unit 550mm - Moon White
89225 Hudson Reed Sarenna Floor Standing WC Unit 550mm - Dove Grey
89238 Hudson Reed Sarenna Floor Standing WC Unit 550mm - Mineral Blue
91446 nuie Arno Floor Standing WC Unit (Concealed Cistern Not Included), 500mm - Satin Anthracite
91460 nuie Arno Floor Standing WC Unit (Concealed Cistern Not Included), 500mm - Satin Grey