https://dba.stackexchange.com/questions/234785/mysql-need-help-making-a-query-faster: trying out WHERE NOT EXISTS

dba_234785.sql

SELECT * FROM (
    SELECT discovery.id, discovery.resource AS url, discovery.event_datetime, whitelisted.keyword 
    FROM discovery
    INNER JOIN whitelisted
    ON discovery.`resource` LIKE concat('%', whitelisted.`keyword`, '%')
    WHERE
    NOT EXISTS (
	    SELECT * FROM `logs` WHERE `logs`.discovery_id = discovery.id
    )
    AND
    discovery.event_datetime >= NOW()
    AND
    discovery.provider = 'XXX'
    AND
    `logs`.id IS NULL
    AND
    discovery.resource NOT LIKE '%SOMETHING-TO-EXCLUDE%'
    LIMIT 0, 20
) logless_resources
GROUP BY logless_resources.url
ORDER BY logless_resources.event_datetime ASC