Preheat oven to 350 and lightly grease a baking dish. (I.5 or 2 quart baking dish will be fine.)
Combine cream cheese, mayo, sour cream, Dijon mustard, Worcestershire sauce, and salt in a mixing bowl. Beat with electric mixer until all combined and smooth.
Stir in shredded (or grated) Monterrey Jack cheese and mozzarella cheese until evenly incorporated.
Go through lump crab meat to make sure there are no shell pieces. Drain and squeeze artichoke hearts. Dice artichoke hearts.
Add crab meat and diced artichoke hearts to the cheese mixture and mix until evenly incorporated.
Spread dip mixture in the baking dish evenly.
For crumb topping: pulse Ritz crackers in a blender until it's just crumbs. Mix crackers with melted butter evenly.
Spread crumb topping all over the top of dip.
Bake for 20 minutes, until bubbly around the edges.