A device may include one or more processors to establish a media access control security (MACsec) key agreement (MKA) session between a first network device and a second network device via a MACsec link; establish a fast heartbeat session via the MACsec communication link, between a first packet processing engine of the first network device and a second packet processing engine of the second network device, to permit the first packet processing engine and the second packet processing engine to exchange fast heartbeat messages via the fast heartbeat session and the MACsec communication link; determine, based on the fast heartbeat session, that the MKA session has ended; and/or perform an action based on the MKA session ending.