SELECT 
  q_product_descriptions.product_id, 
  q_product_descriptions.short_description, 
  IF(
    q_product_descriptions.short_description = '', 
    q_product_descriptions.full_description, 
    ''
  ) AS full_description 
FROM 
  q_product_descriptions 
WHERE 
  q_product_descriptions.product_id IN (
    29282, 29283, 29314, 29341, 29690, 29694, 
    29702, 29799, 30319, 30339, 30770, 
    30781, 30782, 30783, 30787, 30794, 
    30799, 30815, 30860, 30873, 30876, 
    30899, 30911, 30920, 30931, 30937, 
    30939, 30943, 30957, 30972
  ) 
  AND q_product_descriptions.lang_code = 'en'

Query time 0.00084

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "72.01"
    },
    "table": {
      "table_name": "q_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",
      "index_condition": "((`portal`.`q_product_descriptions`.`product_id` in (29282,29283,29314,29341,29690,29694,29702,29799,30319,30339,30770,30781,30782,30783,30787,30794,30799,30815,30860,30873,30876,30899,30911,30920,30931,30937,30939,30943,30957,30972)) and (`portal`.`q_product_descriptions`.`lang_code` = 'en'))",
      "cost_info": {
        "read_cost": "66.01",
        "eval_cost": "6.00",
        "prefix_cost": "72.01",
        "data_read_per_join": "114K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ]
    }
  }
}