id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	SIMPLE	table2	NULL	index	store_id_table2	store_id_table2	8	NULL	6	50.00	Using index; LooseScan
1	SIMPLE	table1	NULL	eq_ref	PRIMARY	PRIMARY	8	db1.table2.store_id	1	100.00	NULL