how many rows do your 2 tables have?

how many rows do are returned if execute
SELECT count(*)
FROM table1
WHERE table1.col3<=SYSDATE
AND (
(
table1.col4='a'
AND
table1.col5<100
)
OR
(
table1.col4='b'
AND
(
table1.col5=10
OR
table1.col5=20
)
)
)
AND table1.col6<>'abc'
AND table1.col6<>'def'
AND table1.col6<>'ghi'

How many rows are retuned if you execute
SELECT count(1)
FROM table2 WHERE table2.colc='xy'
AND table2.cold='z'


How long does the execution of these 2 queries take?

How long does your query take?