Оптимизация SQL скрипта

Подскажите, пожалуста, как можно оптимизировать участок sql query? Если много подзапросов, то работает очень долго:

select distinct u.id,
    SQRT(POW(69.1 * (l.Latitude - 49.8147253578057), 2) +    POW(69.1 * (24.0197496861219 - l.Longitude) * COS(l.Latitude / 57.3), 2)) AS distance 
FROM user u 
    join location l on 
        (l.id = u.location_id and acos(sin(l.Latitude * 0.0175) * sin(49.8147253578057 * 0.0175)  + cos(l.Latitude * 0.0175) * cos(49.8147253578057 * 0.0175) *  
 cos((24.0197496861219 * 0.0175) - (l.Longitude * 0.0175))) * 3959 <= 25) 
    join current_subject c on 
        (c.id in (select id_current_subject from  user_current_subject where id_user = u.id) and c.subject_id = 2
      and 3 in (select id_curriculum from current_subject_curriculum where c.id = id_current_subject)
      and 4 in (select id_curriculum from current_subject_curriculum where c.id = id_current_subject)
        and 7 in (select id_curriculum from current_subject_curriculum where c.id = id_current_subject)
         and 13 in (select id_curriculum from current_subject_curriculum where c.id = id_current_subject)
         and 15 in (select id_curriculum from current_subject_curriculum where c.id = id_current_subject)
         and 16 in (select id_curriculum from current_subject_curriculum where c.id = id_current_subject)
         and 17 in (select id_curriculum from current_subject_curriculum where c.id = id_current_subject)
         and 18 in (select id_curriculum from current_subject_curriculum where c.id = id_current_subject)
         and 25 in (select id_curriculum from current_subject_curriculum where c.id = id_current_subject)
     ) 
 where u.role = 1 
    and u.status >= 103 
    and u.status != 105 
    and u.status != 106 
ORDER BY distance LIMIT 30 OFFSET 0