<?php
function checked($a)
{
    $check = array(
        "id",
        "name",
        "age",
        "email",
        "password",
        "birthday",
        "ip",
        "time",
        "token",
        "source"
    );
    $i     = 0;
    foreach ($a as $key => $value) {
        if (in_array($key, $check)) {
            $i++;
        }
    }
    if ($i == 10) {
        $string = "Все ключи на месте, все $i";
        return $string;
    } else {
        $string = "Найдено всего $i ключей";
        return $string;
    }
}
$a = array(
    "id" => "12345",
    "name" => "Nikita",
    "age" => "23",
    "email" => "htk@gmail.com",
    "password" => "123456",
    "birthday" => "12 october",
    "ip" => "127.0.0.1",
    "time" => "12:12",
    "token" => "tok_en",
    "source" => "so_ur_ce",
'hello' => 'world'
);
echo checked($a);