pdo->prepare('SELECT 1 FROM nonces WHERE nonce = ? LIMIT 1'); $st->execute([$nonce]); return (bool)$st->fetchColumn(); } public function remember(string $nonce, int $expiresAt): void { $st = $this->pdo->prepare('INSERT INTO nonces (nonce, expires_at) VALUES (?, ?)'); $st->execute([$nonce, $expiresAt]); } }