Currently, there's no way to filter the entities based on a field. You can try fetching partial response to retrieve only the fields that you are interested in. For e.g., if you just need the account ID and name, you can make a query like below, which will only return account ID and name for all the accounts.
Also, note that returned account collection is sorted on account ID. So you could use start-index and max-results parameters to further reduce number of accounts returned. Of course, for this to be effective, you would need to know what page your account is on based on its ID.
Jeetendra.