sql - Is there a way to tuneup a complex count query against heavy data? -

there 2 tables 1 empl having 545405 records , second pam having 1466320 records. task find count of pid according aid. acomplish task write following query.

select pa.aid, count(pa.pid)  empl join pam pa on empl.pid = pa.pid group pa.aid 

the indexes pam following:

ix_pam_unique   nonclustered, unique, unique key located on primary     pid, aid ix_pam_aid      nonclustered located on primary                         aid pk_paid         clustered, unique, primary key located on primary       paid 

the actual execution plan shows index scan:

what can understand there estimated data size of 15 mb causing problem.

is there way tuneup complex count query against heavy data?

edit:

the query empl filters:

select pa.aid, count(pa.pid)  empl join pam pa on empl.pid = pa.pid  empl.del = 0 ,  empl.pub = 1 ,  empl.sid = 2 ,  empl.md = 0           group pa.aid 

and there nothing fancy in structures, basic datatypes int, bit, varchar , datatime used. there 65 columns in empl , 4 columns in pam

possible helpful -

select pa.* empl join (     select            pa.aid         , cnt = count(pa.pid)     pam pa      group pa.aid ) pa on empl.pid = pa.pid 

or -

select pa.aid, count(pa.pid) pam pa exists(     select 1      empl      empl.pid = pa.pid ) group pa.aid 

or -

select        pa.aid     , cnt = count(pa.pid) pam pa  group pa.aid