Is the AP using ZoneDirector's DHCP?
Under ZD's Configure/System, DHCP Server, if it's enabled there will be a line at the bottom of the section
that reads "To view all IP addresses that have been assigned by the DHCP server, click here" to produce a
table of current leased IPs and MAC addresses, and I believe Lease time remaining.
Note: Reset/clear DHCP on a ZD by disabling and re-enabling the DHCP service.
From a ZD's CLI and enable mode, 'show dhcp all' will display the same table details.
AP's CLI has 'get ipaddr wan' to show IP address (static or dynamic), netmask, def-gw, but not lease remaining.
From my old Cisco days, I think some switch/routers used "show ip dhcp binding"...?