MySQL GET_LOCK() debugging

-- Return details of what Userspace locks (via GET_LOCK()) are being waited for
-- and what the owning thread is doing, if anything

SELECT
    p1.time as waitingfor,
    SUBSTRING_INDEX(SUBSTRING(p1.info, 18), "'", 1) as lock_key,
    IS_USED_LOCK(SUBSTRING_INDEX(SUBSTRING(p1.info, 18), "'", 1)) as pid,
    p2.*
FROM information_schema.processlist p1, information_schema.processlist p2
WHERE
    p1.info like "SELECT GET_LOCK('%"
HAVING pid = p2.id;