Add this column:
IND_ACTIVO
as an INCLUDEd column to your existing index.
Otherwise, the query plan looks reasonable.
It would be better if you didn't convert for the sort, but you will get a different sort order converting vs not converting.
Btw, I strong suggest you not create (another) nonclus index. Your clus index is (relatively) huge, and SQL will have to add all those columns to any nonclus index you create.
SQL DBA,SQL Server MVP(07, 08, 09) "Money can't buy you happiness." Maybe so, but it can make your unhappiness a LOT more comfortable!