Once you locked your key you have several ways to open the door, only if this is your car. You can find some decent methods on Youtube or Google, but, the best option you can do is locksmith hornsey, yes! it will cost you money but you will save tons of time and you won't make things worse. I know what I am talking about, I've bought several cars with no keys(Scrapeyard) and I had to open them on my own, honestly paying a locksmith everytime I had to open a car would make me a bankrupt so I had to do this several times on my own, but everytime I had to open a car on my own, it made me regret I did not called a locksmith. Those guys knows what they are doing and how to open a lock