How to make locked door and key that opens it.

[HakePT]

void OnStart()
{
AddUseItemCallback("", "awesomekey_1", "mansion_1", "UsedKeyOnDoor", true); --> is your key named "awesomekey_1"? The door name must be "mansion_1" as well.
}

void UsedKeyOnDoor(string &in asItem, string &in asEntity)
{
SetSwingDoorLocked("mansion_1", false, true); --> again door name "mansion_1"?
PlaySoundAtEntity("", "unlock_door", "mansion_1", 0, false);
RemoveItem("awesomekey_1"); --> just to remove the key from inventory after it is used, key name "awesomekey_1"
}

Check the tutorial video on making doors. If you follow step by step you can't go wrong.