high response time for a custom query

Hi

I use Job Manager plugin and I want to search for the locations that their distance are less than 10 Kilometers from input $lang and $lat. I use following query to do this, but it takes many time (more than 6 seconds) to respond. Do you know a better way or better sql query to do this?

$wpdb->prepare( "
           SELECT DISTINCT
           map_lat.post_id,
           p.post_title,
           map_lat.meta_value as locLat,
           map_lng.meta_value as locLong,
            (
   6371 * ACOS(
     COS(RADIANS( %s )) * COS(RADIANS(map_lat.meta_value)) * COS(
       RADIANS(map_lng.meta_value) - RADIANS( %s )
     ) + SIN(RADIANS( %s )) * SIN(RADIANS(map_lat.meta_value))
   )
 ) AS distance
FROM $wpdb->posts p
       INNER JOIN $wpdb->postmeta map_lat ON p.ID = map_lat.post_id
       INNER JOIN $wpdb->postmeta map_lng ON p.ID = map_lng.post_id
       WHERE 1 = 1
       AND p.post_type = 'job_listing'
       AND p.post_status = 'publish'
       AND map_lat.meta_key = 'geolocation_lat'
       AND map_lng.meta_key = 'geolocation_long' 
       HAVING distance < %s
       ORDER BY map_lat.post_id DESC LIMIT 5",
            $lat,
            $long,
            $lat,
            $radius
        );