How is it possible then to know your balance? Do you have to go through all the blocks just to find those transactions that involve the public key of your walle

How is it possible then to know your balance? Do you have to go through all the blocks just to find those transactions that involve the public key of your wallet? This sounds extremely impractical, because the majority of the transactions would not involve yourself. I assume then that there's a way to "query" the blockchain? How does Electrum do it?