fix the getExpiredMACs query
fix the getExpiredMACs query

the database query should only query the MACs not the whole data set

Freifunk-Rhein-Neckar/ffrn-gw-splash,ffrgb/ffrn-gw-splash,ffrgb/ffrn-gw-splash,Freifunk-Rhein-Neckar/ffrn-gw-splash,ffrgb/ffrn-gw-splash