Locked and timed areas are part of Hellfire Club Events, and will unlock at specific times. This means that you will be able to play the event and explore the map until you encounter a locked portal. The locked portal has a timer indicating how much time is left until a new area is available. When the timer hits zero, you are able to access the portal and will be able to further progress on the event. Each event will have a set amount of locked areas, visible on the main event page. You can read more about the Hellfire Club Events in the “What are Hellfire Club Events?” FAQ.