There are some techniques to decompose Toffoli gate. Here I mention two useful techniques. Toffoli gate can be decomposed into six CNOTs (two qubit gate) gates with transpile technique of Qiskit and three CNOTs with Margolus technique. It seems that Margolus technique is the optimal way for decomposing Toffoli gate .
 G. Song and A. Klappenecker, “The simplified toffoli gate implementation by margolus is optimal,” (2003).
With Margolus technique, Fredkin gate(controlled-swap gate) can be decomposed with only 5 qubit gates .
 J. A. Smolin and D. P. DiVincenzo, Phys. Rev. A 53, 2855 (1996).
Here is a simple code that you can use it for decomposing of Toffoli gate with transpile function qiskit
from qiskit.quantum_info import Operator
from qiskit.compiler import transpile
from qiskit import QuantumCircuit, ClassicalRegister, QuantumRegister
qc = QuantumCircuit(3)
qc.ccx(0,1,2) # Toffoli gate
result = transpile(qc, basis_gates=['cx','u3','tdg', 'h', 't'], optimization_level=3)