SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31b184f1c95c67947147be373462f269e2ba9574a1f89dd2cb514d80cf45bd74' 
  AND token = 'JYw5HQZzvzT1kN70lHBuNg+OANnCuBojuawiCIIlXPU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Impossible WHERE noticed after reading const tables