Use the --timeout flag to change the timeout.
herbie shell --seed 2019088 +o rules:numerics
(FPCore (K m n M l)
:name "Maksimov and Kolovsky, Equation (32)"
(* (cos (- (/ (* K (+ m n)) 2) M)) (exp (- (- (pow (- (/ (+ m n) 2) M) 2)) (- l (fabs (- m n)))))))