Need help to improve performance of a query

Hi All,

As per the requirement, need to retrieve the data based on non index column of a table. Table consists of million of records. Please help me to improve the performance.

SELECT  MAX (gl_date)  FROM AP_INVOICES_ALL     WHERE attribute_category = 'abc'  AND attribute6 = 'rewer' AND source = 'fdsd'

Explain Plan:

SELECT STATEMENT ALL_ROWSCost: 435,203 Bytes: 36 Cardinality: 1 

2 SORT AGGREGATE Bytes: 36 Cardinality: 1 

1 TABLE ACCESS FULL TABLE AP.AP_INVOICES_ALL Cost: 435,203 Bytes: 36 Cardinality: 1