protected $_quoteFactory;

public function __construct(
    MagentoQuoteModelResourceModelQuoteCollectionFactory $quoteFactory
) {
    $this->_quoteFactory           = $quoteFactory;

}
public function execute(Observer $observer)
    {
         $quote = $this->_quoteFactory->create()->addFieldToFilter('reserved_order_id', $orderId);
         $quote = $this->_quoteFactory->create()->addFieldToFilter('entity_id', 12);
        $quote = $this->_quoteFactory->create()->addFieldToFilter('base_subtotal_with_discount', 20.0000);
}