query("SELECT name FROM sqlite_master WHERE type = 'table' AND name = 'transactions'")->fetch(); if ($tableExists) { $stmt = $pdo->prepare(" SELECT 1 FROM transactions WHERE user_id = :user_id AND created_at >= datetime('now', '-40 seconds') LIMIT 1 "); $stmt->execute(['user_id' => (int) $userId]); $result = (bool) $stmt->fetch(); } } echo json_encode(['result' => $result]);