Is a faithfully flat map of affine schemes open?

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$\newcommand{\Spec}{\mathrm{Spec}}$

Let $R \rightarrow S$ be a faithfully flat (unital) homomorphism of commutative rings. Does it follow that the corresponding map of topological spaces $\Spec S \twoheadrightarrow \Spec R$ is open?

If not, is there a counterexample where both $R$ and $S$ are finitely generated over the same algebraically closed field?

EDIT: The second question was answered in a comment, but I'm still interested in the first part.