<?php
$json_str = file_get_contents('php://input');
$rdata = json_decode($json_str, true);
$pass = $rdata["password"];
$user = $rdata["username"];
$conn = new mysqli("localhost", "root", "", "users");
$result = $conn->query("SELECT * FROM admins WHERE `login` = '$user'");
while($rs = $result->fetch_array(MYSQLI_ASSOC)) {
    if ($rs["pass"] == $pass)
    {
        $tokenObj->token = "abcdefg";
        $tokenObj->username = $user;
        echo json_encode($tokenObj);
    }
}
?>