A locking device for an anchor configured to connect an accessory to a vehicle. An anchor lever is pivotable for opening and closing the anchor. The locking device includes a lock body defining a fastener aperture receiving therethrough an anchor fastener portion that is rotatable by moving the anchor lever between open and closed positions. A lock lever is pivotable relative to the locked body between locked and unlocked positions. In the unlocked position, the lock lever permits free movement of the anchor lever. In the locked position, the lock lever prevents the anchor lever from being moved from the closed position to the open position. A key post is movably connected to the lock body. The key post is movable by a key from an unsecured position to a secured position. The lock lever is fixed in the locked position when the key post is in the secured position.