How to select users by date of birth?

Question

PHP

Database - mysql
Date of birth field of type DATE
Wrote a function that counts by date how many years, that is, with the date 1994-12-08 it displays 19
years

Answer 1

SELECT * FROM USERS WHERE YEAR(DOB_COLUMN) = YEAR(DOB_USER)

or
But it's not scalable because it searches the entire table.

Answer 2

What's the problem? A link with a get parameter, such as site.ru/users/search?age=19, when selecting where user.birthday > ... and user.birthday < ...