sql - Optimize the SQLite select statement to run a lot faster -

this query want optimize, seems take 30 seconds or run on database around 1.7gb 1.5million rows in peptargetentity , targetmatchentity , thousands in customer table , searchentity table. expect such simple statement take milliseconds complete.

there indexes on :

• customer(searchid)
• peptargetentity(customerid)
• targetmatchentity(customerid)

if has ideas appreciated, in advance.

select  customerid, rank, pepid, targetid, falsepositive    (select  t.customerid, t.rank, t.id pepid, null targetid, t.falsepositive, c.surname, c.firstname peptargetentity t       inner join customer c on t.customerid= c.id          c.searchid = 3265 or 3270 = 0  union  select  t.customerid, t.rank, null pepid, t.id targetid, t.falsepositive, c.surname, c.firstname  targetmatchentity t inner join customer c on t.customerid= c.id   c.searchid = 3265 or 3270 = 0)      order surname asc,firstname asc,rank desc    limit 50    offset 0