this query executing for longer time. Any idea on simplifying this query?

While fetching data from sql db in thingworx , this query executing for morethan 80 seconds. Any idea on simplifying this query?

Query:

SELECT distinct a.cmp , a.engseq , a.it, null as COUNT

FROM ENGINEERING a 

WHERE a.MODEL like 'R24R%' 

AND a.cmp not in ( 

select cmp 

from ENGINEERING

where MODEL like 'R23R%' ) ;