SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f5fefdc40e8d810e09fe7bc5f2d53aa7736ed9292420963799ee2f1837f70bb' 
  AND token = 'vb+gTK6p6Z/cvY7MuEtpAOZ7ppgwOLyQXKlFw0KaBf8=' 
  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