create table users
(
  id int,
  email varchar(100),
  is_active tinyint(1),
  created_at int
);

insert into users values (1, 'user@mail.ru', 1, unix_timestamp());
insert into users values (2, 'user@mail.ru', 1, unix_timestamp() + 1234);
insert into users values (3, 'user@mail.ru', 0, unix_timestamp() + 123456);

create view ordered_users as
select * from users order by is_active desc, created_at desc;

select id, email, created_at as created_at
from ordered_users
group by email

select id, distinct email, created_at as created_at
from (select * from users order by is_active desc, created_at desc) as u
group by email