Place butter beans, salt, chili flakes, and thyme in a large pot, and cover with cold water. Make sure water covers the beans by at least 1 inch, and then bring to a boil over high heat. Continue cooking for 5-10 minutes, or until beans are tender. Then drain and run cold water over them, to stop the cooking process. Discard thyme and set beans aside.
While the beans are simmering, warm olive in a small pan, and add garlic cloves. Simmer gently until garlic is fragrant. Remove garlic cloves from oil. Set aside.
Meanwhile, juice lemons into a large bowl. Slowly add the olive oil, whisking constantly to create an emulsion. Season with salt and pepper.
Add butter beans and celery to the lemon vinaigrette with more salt and pepper to taste. Toss. Enjoy!