Вот и пруфы подъехали. Незначительные расхождения по времени. Стоит заметить что таблицы в базе довольно объёмные.

select l.status, array_agg(r.route_name) from routes r join route_nodes rn on r.route_id = rn.route_id join locations l on l.location_id = rn.location_id where r.status = 34 group by l.status

Planning Time: 1.261 ms Execution Time: 1080.905 ms Timing: Generation 8.179 ms, Inlining 0.000 ms, Optimization 2.892 ms, Emission 39.771 ms, Total 50.842 ms

select l.status, array_agg(r.route_name) from routes r, route_nodes rn, locations l where 1=1 and r.status = 34 and r.route_id = rn.route_id and l.location_id = rn.location_id group by l.status

Planning Time: 1.707 ms Execution Time: 1024.166 ms Timing: Generation 8.284 ms, Inlining 0.000 ms, Optimization 3.059 ms, Emission 40.106 ms, Total 51.448 ms