Hey Ravi,
Click "advanced search" (or "Search for product keys" in the dashboard) and in the email field you can search for anything using the wildcard character (*).
Partial email in search
RaviA feature request for your search key web page. We are on a plus plan with 100+ keys initially. The keys page shows 20 results per page which means a browser based partial search does not cut it. when I do a search for a key based on email it expects the full email. Can it support partial email say "yatt" rather than type "wyatt@wyday.com" . While it is not critical, it is a nice to have, as it is easier to search. Reason is, typically emails formed by first and last names, and I could easily search based on first name to determine the key rather than lookup the full email in our internal database and then type it in here.