You’ll need to correctly index the table to work for the query.
The columns in the WHERE clause should be the columns in the index. The columns which are returned but not in the WHERE clause should be included columns.
Indexing is not necessarily the right answer and indexes applied under the wrong circumstance can be counter-productive. I suggest you look at the querie’s execution plan and find where the time is spent. You can the put your efforts into the appropriate area.
You need to look at defragmenting your indexes and shrinking any unused table space too.