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 (
    99086, 99087, 99088, 99089, 99090, 99091, 
    99092, 99093, 99094, 99095, 99096, 
    99097, 99098, 99099, 99100, 99101, 
    99102, 99103, 99104, 99105, 99106, 
    99107, 99108, 99109, 99114, 99213, 
    99214, 99215, 99234, 99235, 99236, 
    99237, 99238, 99240, 99264, 99265, 
    99266, 99268, 99269
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00082

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "17.57"
    },
    "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": 39,
      "rows_produced_per_join": 39,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "13.67",
        "eval_cost": "3.90",
        "prefix_cost": "17.57",
        "data_read_per_join": "148K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (99086,99087,99088,99089,99090,99091,99092,99093,99094,99095,99096,99097,99098,99099,99100,99101,99102,99103,99104,99105,99106,99107,99108,99109,99114,99213,99214,99215,99234,99235,99236,99237,99238,99240,99264,99265,99266,99268,99269)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}