CREATE TABLE IF NOT EXISTS `tokens2` (
  `file` varchar(256) NOT NULL,
  `token` varchar(32) NOT NULL,
  `expire` int(11) NOT NULL
) ENGINE=MyISAM

<?php
function url ($file, $expire) {
    $token = md5(uniqid(rand(), true));
    $expire = time() + $expire;
    $mysqli = new mysqli('localhost', 'root', '', 'database_1');
    $s = $mysqli->prepare("INSERT INTO tokens2 VALUES (?, ?, ?)");
    $s->bind_param('ssi', $file, $token, $expire);
    $s->execute();
    $s->close();
    return 'test.php?' . http_build_query(array(
        'file' => $file,
        'token' => $token
    ));
}
function validate ($file, $token) {
    $expire = null;
    $mysqli = new mysqli('localhost', 'root', '', 'database_1');
    $s = $mysqli->prepare("SELECT expire FROM tokens2 WHERE file=? AND token =?");
    $s->bind_param('ss', $file, $token);
    $s->execute();
    $s->bind_result($expire);
    $s->fetch();
    $s->close();
    if (null !== $expire) {
        $expired = time() > $expire;
        if ($expired) {
            $s = $mysqli->prepare("DELETE FROM tokens2 WHERE file=?");
            $s->bind_param('s', $file);
            $s->execute();
            $s->close();
        }
        return ! $expired;
    }
    else {
        die ('Invalid file or token');
    }
}
function handle ($file, $token) {
    if (true === validate($file, $token)) {
        header('Location: /files/' . $file);
    }
    else {
        die ('Link expired');
    }
}

<?php
require 'token.php';
if (isset($_GET['file']) and isset($_GET['token'])) {
    handle($_GET['file'], $_GET['token']);
}
else {
    ?><a href="<?php echo url('1.jpg', 60); ?>" target="_blank">1.jpg (Expire after 60 sec.)</a><?php
}