Hyperplanes in $SL_2(\mathbb{R})$ containing conjugacy classes of matrices

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Let $SL_2(K)$ be the special linear group of rank 2 over a field $K$, as an affine group scheme cut out by the equation $ad - bc = 1$ in $\mathbb{A}^4_K$.

Let $H$ be an arbitrary, homogeneous, hyperplane, which contains the identity $I$ of $SL_2(K)$ as a point. For example, take $H: 2c - d + a = 0$. (I am particularly interested in this hyperplane).

Is it possible for $H$ to contain an entire conjugacy class besides that of the identity?