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 (
    96944, 96945, 96946, 96947, 96951, 96952, 
    96953, 98889, 98890, 98900, 98902, 
    98903, 100227, 100242, 100243, 100244, 
    100245, 100246, 100247, 100357, 100359, 
    100360, 100445, 100446, 100447, 100461, 
    100462, 100463, 100466, 100469, 100475, 
    100476, 101545, 101546, 101634, 101956, 
    101957
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00094

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "16.67"
    },
    "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": 37,
      "rows_produced_per_join": 37,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "12.97",
        "eval_cost": "3.70",
        "prefix_cost": "16.67",
        "data_read_per_join": "141K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (96944,96945,96946,96947,96951,96952,96953,98889,98890,98900,98902,98903,100227,100242,100243,100244,100245,100246,100247,100357,100359,100360,100445,100446,100447,100461,100462,100463,100466,100469,100475,100476,101545,101546,101634,101956,101957)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}