There are keys in some kind of box which is open.
A man is looking for the box
The first sentence does not suggest anybody is looking for the box.
exists p1 x1 s1 x2 x3 x4 x5.((x1 = x2) & in(x2,x3) & Theme(s1,x5) & a_open(s1) & (x3 = x5) & of(x3,x4) & n_box(x4) & n_kind(x3) & n_key(x2))
exists e1 x1 x2.(n_box(x2) & for(e1,x2) & Actor(e1,x1) & v_look(e1) & n_man(x1))