Why doesn't it matter?

[Bogopo]

$token = $_GET["token"];
$stmt = $pdo->prepare("SELECT token FROM Tokens WHERE token =? LIMIT 1");
$stmt->execute(array($token));
echo $stmt->fetchColumn(PDO::FETCH_ASSOC);

The answer is empty.

What's the problem?

[yajahira]

$token = $_GET["token"];
$stmt = $pdo->prepare("SELECT token FROM Tokens WHERE token =? LIMIT 1");
$stmt->execute(array($token));

if($stmt->rowCount() == 1) {
    echo $stmt->fetchColumn(0);
}