Indexes when left joining 2 tables with order by on second table MySQL

This may be so easy for an experienced user, but I'm no able to fully understand what indexes are needed for this simple case.

I have a front-end table that can be sorted by any column besides some filters that can be applied for searching purposes:

id | username | email | name | phone | email_verified_at

The rows shown is a result of joining 2 tables (with a one-to-one relationship):

TABLE USERS

id | autoincrement
name | string
username | string | unique
email | string | unique
email_verified_at | timestamp | nullable

INDEXES
primary(id)
unique(name,id)
unique(username)
unique(email)
unique(email_verified_at,email)

TABLE PROFILES

id | autoincrement
user_id | FK(users)
phone | string

INDEXES
primary(id)
index(user_id)
unique(phone,user_id)

The most basic query, ordered by user id looks like

select
  `users`.`id` as `id`,
  `users`.`name` as `name`,
  `users`.`username` as `username`,
  `users`.`email` as `email`,
  `users`.`email_verified_at` as `email_verified_at`,
  `profiles`.`phone` as `phone`
from
  `users`
  left join `profiles` on `users`.`id` = `profiles`.`user_id`
order by
  `id` asc
limit
  11

Ordering by id, name, username, email, or email_verified_at performs a FULL INDEX SCAN in users table which I assume is correct.

But the trouble (or not) comes when I try to order by phone:

select
  `users`.`id` as `id`,
  `users`.`name` as `name`,
  `users`.`username` as `username`,
  `users`.`email` as `email`,
  `users`.`email_verified_at` as `email_verified_at`,
  `profiles`.`phone` as `phone`
from
  `users`
  left join `profiles` on `users`.`id` = `profiles`.`user_id`
order by
  `phone` asc
limit
  11

The first thing I see is that it's doing a FULL TABLE SCAN in users table. In order to avoid that I need to create a UNIQUE index for users table containing:

id, username, email, name

Therefore the query performs a FULL INDEX SCAN over users table. Despite that, I'm seeing that query cost is too high compared to sorting by users table fields.

Is that OK? Am I missing something here? I'm not sure if this is an expected result or it can be improved.

Thanks in advance