SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c7d3c171be0de8e6ae99200d6fef57703f99f9e0d8aa8699f217c8b34e45b1b' 
  AND token = 'xN8hUvjdKk/tsjRIohySInaAlqRwkO+WowItjL8R8Rs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

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