**Update 2.** Now the proof should be more readable. I deleted some content because it is replaced by more elegant version.
The equation is unsolvable. The proof requires two theorems

**Theorem 1.** Let $p = a^2 + 8b^2 \equiv 1 \pmod{8}$, $\gcd(a, b) = 1$, every prime divisor of $p$ is 1 modulo 8. Then $p$ has an even number of prime divisors for which 2 is not a fourth power if and only if $a \equiv \pm 1 \pmod{8}$.

**Theorem 2.** Let $p = a^2 - 8b^2 \equiv 1 \pmod{8}$, $\gcd(a, b) = 1$, every prime divisor of $p$ is 1 modulo 8. Then $p$ has an even number of prime divisors for which 2 is not a fourth power if and only if $a \equiv 1, 3 \pmod{8}$.

I will prove the first theorem. Let $q$ be a prime divisor of $p$. $-(ab)^2 \equiv 8b^4 \pmod{q}$. Since -1 is a fourth power modulo $q$, 2 will be a fourth power modulo $q$ if and only if $ab$ is a quadratic residue. Therefore we can reformulate the theorem in terms of Jacobi symbols:
$$\prod_{q \mid p, q \in \mathbb{P}} \left(\frac{ab}{q}\right) = \left(\frac{ab}{p}\right) = \left(\frac{2}{a}\right)$$
And the proof becomes simple.
$$\left(\frac{ab}{p}\right) = \left(\frac{a}{p}\right)\left(\frac{b_1}{p}\right) = \left(\frac{a^2 + 8b^2}{a}\right)\left(\frac{a^2 + 8b^2}{b_1}\right) = \left(\frac{2}{a}\right)$$
where $b = b_1 \cdot 2^k$, $b_1 \equiv 1 \pmod{2}$.

Will Jagy showed that the representation
$$ p = (x^2 + 4)^2 - 2(2x + 4)^2 $$
is primitive and $p$ is not divisible by any prime $q \equiv \pm 3 \pmod{8}$. Then from $p = u^2 + 32v^2$ we see that $d = \gcd(u, v) \equiv \pm 1 \pmod{8}$, $p = p_1d^2$, $p_1$ has only divisors of the form $8k + 1$. $u \equiv \pm 1 \pmod{8}$ since $p \equiv 1 \pmod{16}$. 
$$p_1 = \left(\frac{u}{d}\right)^2 + 8 \left(\frac{v}{d}\right)^2$$
Applying theorem 1 we obtain that $p$ is divisible by an even number of prime divisors of the form $8k + 1$ for which 2 is not a fourth power.

$$p_1d^2 = (x^2 + 4)^2 - 2(2x + 4)^2$$
Applying theorem 2 we obtain
$$\left(\frac{(x^2 + 4)(2x + 4)}{p_1}\right) = \left(\frac{(x^2 + 4)(2x + 4)}{p_1d^2}\right) = \left(\frac{-2}{x^2 + 4}\right) = -1 $$
Therefore $p$ is divisible by an odd number of prime divisors of the form $8k + 1$ for which 2 is not a fourth power. And this is a contradiction.