USB 5v temp control for stainless steel wire micro heat elenent
Heat capacity of water is about 4.2J/gK. 

Heating 1ml (1g) of water from 20C to 60C (40K increase) thus requires about 170J of energy. 

You can typically get 100mA to 500mA @5V from a common USB 2.0 compliant port. 

So at 100mA (0.5J/s) it would take 5 or 6 minutes, ignoring losses. At 500mA it would take a bit over a minute. So maybe it will actually take a couple minutes at 500mA. 

Losses are inevitable, and will determine how fast the water cools for your "cycling", so they should be controlled in your design. Maybe you want to assume Newtonian losses at something like 0.01W/K above 20'C, and see how that works out. 

This is outside of "electronic" design, however you can use SPICE (eg. LTspice) to simulate thermal systems by using capacitance to represent heat capacity and resistance to represent thermal resistance (time remains time). There are online examples.