This query attempts to delete expired events with special handling for recurring events. Use at own risk!

cleanup-events-query.sql

-- Delete expired events.
--
-- Use at own risk and consider running on a test set of data first of all!
-- As is, should remove all events that have expired by more than one week,
-- with the exception of parent events for recurring events which will be
-- left in place.
--
-- Assumes a standard table prefix of "wp_" - adjust as required to match
-- your installation.
DELETE FROM wp_posts
WHERE post_type = 'tribe_events'

-- Special handling for recurring events
AND (
        -- Expired children? Safe to remove
        post_parent > 0
        
        -- Expired non-children? Remove only if they are not recurring events
        OR ID NOT IN (
            SELECT DISTINCT( post_id )
            FROM wp_postmeta
            WHERE meta_key = '_EventRecurrence'
            -- The following serialized data means "I am not a recurring event"
            AND meta_value <> 'a:3:{s:5:"rules";a:0:{}s:10:"exclusions";a:0:{}s:11:"description";N;}'
        )
)
    
-- Consider expired events to be ones that ended more than one week ago 
-- (adjust interval if needed)
AND ID IN (
    SELECT DISTINCT( post_id )
    FROM wp_postmeta
    WHERE meta_key = '_EventEndDate'
    AND   meta_value < ( NOW() - INTERVAL 1 WEEK )
)

Note: it's possible that long-lived installations will include non-recurring events with a slightly different _EventRecurrence string than is anticipated above. Therefore if expired, non-recurring events are not removed on first run that would be worth looking at.