How can I optimize this query and support multiple SKUs?

My current query only can select one SKU at a time. I can leave salesite_id constant. If there is a way to also have varying salesite_ids that would be good too, but not necessary. Also any suggestions on indexes would be much appreciated also. SELECT available - ( SELECT COALESCE(sum(quantity), 0) FROM product_locks WHERE sku = 'sku1' ) - ( SELECT COALESCE(sum(quantity), 0) FROM orderlineitems INNER JOIN responses_authnets ON responses_authnets.id = orderlineitems.response_id WHERE sku = 'sku1' AND responses_authnets.salesite_id = 'site_id_1' ) AS free, available AS total, sku, on_hold FROM product_inventories WHERE sku = 'sku1' AND salesite_id = 'site_id_1';