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 (
    86254, 86306, 86312, 86328, 86345, 86349, 
    86273, 86305, 86296, 86322, 86340, 
    86341, 86266, 86287, 86294, 86320, 
    86264, 86285, 95152, 95153, 95154, 
    95155, 95156, 95157, 95158, 95166, 
    95167, 95169, 95170, 95172
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00076

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 (86254,86306,86312,86328,86345,86349,86273,86305,86296,86322,86340,86341,86266,86287,86294,86320,86264,86285,95152,95153,95154,95155,95156,95157,95158,95166,95167,95169,95170,95172)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
86254 nuie Revive Double Panel Designer Radiator 1800 x 354mm - High Gloss White
86264 nuie Revive Horizontal Double Panel Radiator 600 x 412mm - High Gloss White
86266 nuie Revive Horizontal Double Panel Radiator 600 x 586mm - High Gloss White
86273 nuie Revive Double Panel Designer Radiator 1500 x 354mm - High Gloss White
86285 nuie Revive Horizontal Double Panel Radiator 600 x 412mm - Anthracite
86287 nuie Revive Horizontal Double Panel Radiator 600 x 586mm - Anthracite
86294 nuie Sloane Horizontal Double Panel Radiator 600 x 412mm - Anthracite
86296 nuie Sloane Horizontal Double Panel Radiator 600 x 586mm - Anthracite
86305 nuie Revive Double Panel Designer Radiator 1500 x 354mm - Anthracite
86306 nuie Revive Double Panel Designer Radiator 1800 x 354mm - Anthracite
86312 nuie Xcite Xcite Designer Radiator 1775 x 450mm - Anthracite
86320 nuie Sloane Horizontal Double Panel Radiator 600 x 412mm - Satin White
86322 nuie Sloane Horizontal Double Panel Radiator 600 x 586mm - Satin White
86328 nuie Xcite Xcite Designer Radiator 1775 x 450mm - High Gloss White
86340 nuie Revive Compact Designer Radiator 1800 x 237mm - High Gloss White
86341 nuie Revive Compact Designer Radiator 1800 x 237mm - Anthracite
86345 nuie Salvia Designer Radiator 1500 x 383mm - High Gloss White
86349 nuie Salvia Designer Radiator 1500 x 383mm - Anthracite
95152
95153
95154
95155
95156
95157
95158
95166
95167
95169
95170
95172