Fastest way to do meta query when I don’t need the actual posts, and just need post_id?

In wordpress I often use $wpdb to just do my queries manually when I just need to extract some value.

In my case, I have a Membrepress rule that could be tied to some content type. The rule’s meta includes two keys that I am trying to query on: _mepr_rules_type and _mepr_rules_content.

I know I can do something like this:

$args = array(
    'post_type' => 'memberpressrule',
    'posts_per_page' => -1,
    'meta_query' => array(
        'relation' => 'AND',
        array(
            'key' => '_mepr_rules_content',
            'value' => 885,
            'compare' => '='
        ),
        array(
            'key' => '_mepr_rules_type',
            'value' => 'single_sfwd-lessons',
            'compare' => '='
        )
    )
);
$results = new WP_Query($args);

But it seems overkill when I simply want the rule id.

I see that WordPress is constructing the query as

SELECT   wp_posts.* FROM wp_posts  INNER JOIN wp_postmeta ON ( wp_posts.ID = wp_postmeta.post_id )  INNER JOIN wp_postmeta AS mt1 ON ( wp_posts.ID = mt1.post_id ) WHERE 1=1  AND ( 
  ( wp_postmeta.meta_key = '_mepr_rules_content' AND wp_postmeta.meta_value = '885' ) 
  AND 
  ( mt1.meta_key = '_mepr_rules_type' AND mt1.meta_value = 'someruletype' )
) AND wp_posts.post_type = 'memberpressrule' AND (wp_posts.post_status = 'publish' OR wp_posts.post_author = 34 AND wp_posts.post_status = 'private') GROUP BY wp_posts.ID ORDER BY wp_posts.post_date DESC 

Is there any reason to deal with WP_Query? I mean, I really don’t want to deal with resetting global $post and other headaches that one ends up with when using queries inside an existing post loop. So would doing this manual query be the fastest way?

global $wpdb;
$sql = "SELECT   wp_posts.ID FROM wp_posts  INNER JOIN wp_postmeta ON ( wp_posts.ID = wp_postmeta.post_id )  INNER JOIN wp_postmeta AS mt1 ON ( wp_posts.ID = mt1.post_id ) WHERE 1=1  AND ( 
  ( wp_postmeta.meta_key = '_mepr_rules_content' AND wp_postmeta.meta_value = '885' ) 
  AND 
  ( mt1.meta_key = '_mepr_rules_type' AND mt1.meta_value = 'someruletype' )
) AND wp_posts.post_type = 'memberpressrule' AND (wp_posts.post_status = 'publish' OR wp_posts.post_author = 34 AND wp_posts.post_status = 'private') GROUP BY wp_posts.ID ORDER BY wp_posts.post_date DESC"
$results = $wpdb->get_results($sql);

Also, any reason why I need to join on wp_posts, if the wp_postmeta table itself contains the data I need?

Curious if anyone has ideal method to extract the sort of data I am trying to retrieve.

Thanks!