The query in that execution plan is quite a bit different than what you posted.

In the execution plan, you're doing a convert on the invoice date.  What is the datatype of that date column?

You're also searching for an invoice balance of '0', which is a string rather than a numeric so please identify the datatype of the invoice column, as well.

The only thing that may make this faster is an index on the WHERE criteria and, even then, it may result in an index scan simply because it needs to a scan to enumerate the rows.