same query multiple tables mysql

I have 2 tables in mysql db

T1 : registration
T2 : multiple_email

and I have a field email_id in both the tables. I want to run a query to see if a email is valid. So, I can run 2 queries as

select count(*) from registr开发者_StackOverflowation where emailid = $emailid
select count(*) from multiple_email where emailid = $emailid 

and if one of the count is greater than 0, I consider it as a valid email.

Is there an elegant way of doing it in single query?

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select count(*) + 
(select count(*) from multiple_email where emailid = $emailid)
from registration where emailid = $emailid

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I think it's better to use 2 queries with some changes:

select emailid from registration where emailid = $emailid ;
select emailid from multiple_email where emailid = $emailid 

It will be faster than count(*) because you will read from index only. If emailid is not primary key you can add limit 1.