Wpdb->last_query returns bad query

I use Wordpress 4.8 and I want to get users by meta values. I want users not connected since 7 days, and with 'email_not_logged' meta empty.

So I tried :

$users = get_users(array( 'meta_query' => array( 'relation' => 'AND', array( 'meta_key' => 'last_login', //'meta_value' => 'DATE_SUB(NOW(),INTERVAL 7 DAY)', 'meta_value' => date('Y-m-d H:i', strtotime('-7 days')), 'meta_compare' => '<=', 'type' => 'DATE', ), array( 'meta_key' => 'email_not_logged', 'meta_compare' => 'NOT EXISTS', ) )) ); global $wpdb; echo "<pre>"; print_r($wpdb->last_query); echo "</pre>"; 

I don't know why but I get :

SELECT user_id, meta_key, meta_value FROM ma_usermeta WHERE user_id IN (82) ORDER BY umeta_id ASC

How can I have the good query to test it ?

But, this works :

$users = get_users( array( 'meta_key' => 'last_login', //'meta_value' => 'DATE_SUB(NOW(),INTERVAL 7 DAY)', 'meta_value' => date('Y-m-d H:i:s', strtotime('-7 days')), 'meta_compare' => '<=', 'type' => 'DATE', ) ); 

Do I use badly meta_query ?