SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a47af26e620e9dc2f7dd68db98a50b84ecbfebb8721d1411cffa3bbc0ca8bde' 
  AND token = 'QS6WTmXKrfICZBgoAwj0h8nRVFrnOYeKXiTMqKKpS/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}