The key server on MacGIS (the Cartographica web site), sends out keys as soon as you request them. If you haven't yet received your key, you may want to check your spam filters to make sure the message hasn't been caught. The messages are sent from keymanager at cluetrust dot com, and so excluding that address from your spam filter should help.
If you still can't find it, try our Lost Key page and we'll send you another notice. If that doesn't work, please contact support directly and we will work with you to resolve the problem.