I'll assume timeDate is indexed. Now taking substrings of indexes pretty much makes it like the index doesn't exist, and hence slower queries (actually, performing functions on fields makes it slower in general). Now what I would do, if my assumption is correct and if you're looking for all logins from 2003-09-03 is to rewrite your query to:
WHERE timeDate >= '2003-09-03 00:00:00'
and timeDate < '2003-09-04 00:00:00'
or something like that. And if you're looking for login's for today, you could omit the "and"