sql.log logs only CREATE, DROP, and ALTER table.
INSERTs, UPDATEs and SELECTs are logged one at the time in the db._lastsql string.
To check whether caching is used you can do
db._lastsql=None
rows=db(...).select(...,cache=(cache.ram,60))
if db._lastsql:
print 'SQL WAS EXECUTED AND RESULT CACHED:',db._lastsql
else:
print 'SQL WAS NOT EXECUTED, DATA RETRIEVED FROM CACHE'