limit & scala subquery

[jongse park]

I confused the order of mysql sql excution.
table t1 has 1 billion records.

ex)
select col1, col2, (scalar subquery .. table t1)
from t1, t2
where t1.col3 = t2.col3
order by col3
limit 45;

in above case, when dose scalar subquery excute? after limit 45?
or after order by ?