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 (
    89391, 89393, 89406, 89408, 89407, 90843, 
    89302, 89384, 89389, 89300, 89301, 
    89299, 89349, 89350, 89263, 89353, 
    89354, 89355, 89356, 89293, 89291, 
    89262, 89292, 89287, 89357, 89358, 
    89402, 89404, 89403, 89295
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "13.52"
    },
    "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": 30,
      "rows_produced_per_join": 30,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "10.52",
        "eval_cost": "3.00",
        "prefix_cost": "13.52",
        "data_read_per_join": "114K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (89391,89393,89406,89408,89407,90843,89302,89384,89389,89300,89301,89299,89349,89350,89263,89353,89354,89355,89356,89293,89291,89262,89292,89287,89357,89358,89402,89404,89403,89295)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
89262 nuie Thermostatic Concealed Twin Round Valve & Slide Rail Kit with Multi Function Handset & Outlet Elbow Shower Kit - Chrome
89263 nuie Thermostatic Concealed Twin Round Valve, Wall Mount Shower Arm & Round Fixed Head Shower Kit - Chrome
89287 nuie Binsey Thermostatic Concealed Twin Round Valve & Slide Rail Kit with Multi Function Handset & Outlet Elbow Shower Kit - Chrome
89291 nuie Binsey Thermostatic Concealed Twin Round Valve, Wall Mount Shower Arm & Round Fixed Head Shower Kit - Chrome
89292 nuie Arvan Thermostatic Concealed Twin Round Valve & Slide Rail Kit with Multi Function Handset & Outlet Elbow Shower Kit - Chrome
89293 nuie Arvan Thermostatic Concealed Twin Round Valve, Wall Mount Shower Arm & Round Fixed Head Shower Kit - Chrome
89295 nuie Binsey Manual Concealed Twin Round Valve with Diverter, Slide Rail Kit with Multi Function Handset & Outlet Elbow Wall Mount Shower Arm & Round Fixed Head Shower Kit - Chrome
89299 nuie Binsey Thermostatic Concealed Twin Round Valve with Diverter, Slide Rail Kit with Multi Function Handset & Outlet Elbow Wall Mount Shower Arm & Round Fixed Head Shower Kit - Chrome
89300 nuie Binsey Thermostatic Concealed Triple Round Valve, Slide Rail Kit with Multi Function Handset & Outlet Elbow Wall Mount Shower Arm & Round Fixed Head Shower Kit - Chrome
89301 nuie Arvan Thermostatic Concealed Twin Round Valve with Diverter, Slide Rail Kit with Multi Function Handset & Outlet Elbow Wall Mount Shower Arm & Round Fixed Head Shower Kit - Chrome
89302 nuie Arvan Thermostatic Concealed Triple Round Valve, Slide Rail Kit with Multi Function Handset & Outlet Elbow Wall Mount Shower Arm & Round Fixed Head Shower Kit - Chrome
89349 nuie Thermostatic Concealed Twin Square Valve & Slide Rail Kit with Single Function Handset & Outlet Elbow Shower Kit - Chrome
89350 nuie Thermostatic Concealed Twin Square Valve, Wall Mount Shower Arm & Square Fixed Head Shower Kit - Chrome
89353 nuie Windon Thermostatic Concealed Twin Square Valve & Slide Rail Kit with Single Function Handset & Outlet Elbow Shower Kit - Chrome
89354 nuie Windon Thermostatic Concealed Twin Square Valve, Wall Mount Shower Arm & Square Fixed Head Shower Kit - Chrome
89355 nuie Sanford Thermostatic Concealed Twin Square Valve & Slide Rail Kit with Single Function Handset & Outlet Elbow Shower Kit - Chrome
89356 nuie Sanford Thermostatic Concealed Twin Square Valve, Wall Mount Shower Arm & Square Fixed Head Shower Kit - Chrome
89357 nuie Windon Manual Concealed Square Valve, Slide Rail Kit with Single Function Handset & Outlet Elbow Wall Mount Shower Arm & Square Fixed Head Shower Kit - Chrome
89358 nuie Sanford Manual Concealed Square Valve, Slide Rail Kit with Single Function Handset & Outlet Elbow Wall Mount Shower Arm & Square Fixed Head Shower Kit - Chrome
89384 Hudson Reed Dual Exposed Valve & Slide Rail Kit - Chrome
89389 nuie Victorian Traditional Dual Exposed Valve & Single Function Slide Rail Shower Kit - Chrome/White
89391 nuie Victorian Traditional Twin Exposed Valve & Single Function Slide Rail Shower Kit - Chrome/White
89393 nuie Edwardian Traditional Twin Exposed Valve & Single Function Slide Rail Shower Kit - Chrome/White
89402 nuie Traditional Manual Concealed Valve & Single Function Slider Rail Kit & Outlet Elbow - Chrome/White
89403 nuie Traditional Manual Concealed Valve, Wall Mount Shower Arm and Round Fixed Head Shower Kit - Chrome/White
89404 nuie Traditional Manual Exposed Valve & Single Function Slider Rail Kit & Outlet Elbow - Chrome/White
89406 nuie Victorian Traditional Thermostatic Concealed Twin Valve & Single Function Slider Rail Kit & Outlet Elbow - Chrome/White
89407 nuie Victorian Traditional Thermostatic Concealed Twin Valve, Wall Mount Shower Arm and Round Fixed Head Shower Kit - Chrome/White
89408 nuie Edwardian Traditional Thermostatic Concealed Twin Valve & Single Function Slider Rail Kit & Outlet Elbow - Chrome/White
90843 nuie Edwardian Traditional Thermostatic Concealed Twin Valve, Wall Mount Shower Arm and Round Fixed Head Shower Kit - Chrome/White