It's not a big issue but some index are mising on small tables:
ezpolicy_limitation.policy_id
ezworkflow_event index on (`version`,`workflow_id`)

ezp generate this query:
SELECT id, policy_id, identifier
FROM ezpolicy_limitation
WHERE policy_id='1208'
ORDER BY id ASC;

and
SELECT id, placement
FROM ezworkflow_event
WHERE workflow_id='3' AND version='0'
ORDER BY placement ASC
LIMIT 2, 1;

also missing on ezuser_accountkey.hash_key

SELECT id, user_id, hash_key, time
FROM ezuser_accountkey
WHERE hash_key='52438d2fe681326422b56711d5f1b1f6';