There are few tables referenced through DATABASE_1 database in those crash queries. Those references are not tables, actually views on top of another database. Since explain statements show these underlying tables only, Please use the below view definition for your analysis so that mapping can be done accordingly.

1) CREATE VIEW DATABASE_1.TABLE_6 AS SELECT a.* FROM DATABASE_1_CORE.TABLE_6 a

2) CREATE VIEW DATABASE_1.TABLE_1 AS SELECT a.* FROM DATABASE_1_CORE.TABLE_1 a INNER JOIN DATABASE_1_CORE.TABLE_5 b ON a.tenant_key = b.tenant_key WHERE tenant_id = 0

3) CREATE VIEW DATABASE_1.TABLE_3 AS SELECT a.* FROM DATABASE_1_CORE.TABLE_3 a LEFT OUTER JOIN DATABASE_1_CORE.TABLE_5 b ON a.tenant_key = b.tenant_key WHERE (b.tenant_id = 0 OR b.tenant_id IS NULL)

4) CREATE VIEW DATABASE_1.TABLE_4 AS SELECT a.* FROM DATABASE_1_CORE.TABLE_4 a

5) CREATE VIEW DATABASE_1.TABLE_4_instance AS SELECT a.* FROM DATABASE_1_CORE.TABLE_4_instance a

6) CREATE VIEW DATABASE_1.TABLE_2 AS SELECT a.* FROM DATABASE_1_CORE.TABLE_2 a LEFT OUTER JOIN DATABASE_1_CORE.TABLE_1 b ON a.customer_key = b.customer_key LEFT OUTER JOIN DATABASE_1_CORE.TABLE_5 c ON b.tenant_key = c.tenant_key WHERE (c.tenant_id = 0 OR c.tenant_id IS NULL)