I have a very high volume form that, upon saving, must update a record in a table with about 280.000 records. All of the relevant fields in the table are indexed. I have tried the two methods below, both with about the same performance results.

UPDATE temptest!join_cancel; && EXPIRE record to reflect new paid thru date
SET jdate = current_paid_thru;
WHERE join_cancel.jmembnum = memb.membnum;
AND join_cancel.activity = "EXPIRE"

and

replace jdate with current_paid_thru for join_cancel.jmembnum = memb.membnum .and. join_cancel.activity = EXPIRE"

They each take about 5 seconds to execute. This is unacceptable. Is there something I am overlooking? Is there anything else I need to index or a different way I should be updating this record? I have several other tables with records in the millions that only take a split second to query. Please help, I am at wits end. I am in big trouble if this is the performance I have to live with.