I work at Co-Op bank and i run queries with just uner 1 million records at a time and are usually reuturned within in a few seconds on a normal windows nt box. Therefore on a server like this one this will not be a problem.
Or maybe just store the ip address and the id of the script for the vote it made. Therefore you could just be able to
code:
"SELECT COUNT(*) FROM tbllog WHERE ip ='" & ip & "' AND id=" & id
This would be the best option.