我应该使用哪个索引来混合WHERE和ORDER BY

Question

I have following query

SELECT * FROM mytable WHERE toshow = 1 ORDER BY timestamp DESC

The timestamp column stores current timestamp in database when inserting row. In some rows 'toshow' value is 0 and in some rows its 1

What INDEX should I use to get results faster for any 0 or 1 toshow value and latest row above

I created index (timestamp, toshow) for this but confusing its right or not.

Answer 1

Covering index:

CREATE INDEX idx ON mytable(toshow, timestamp DESC);