SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '308a108252bc4d33a83cae716c7f4d68281de7b3ee1e1864f113739ede23a97a' 
  AND token = 'HQHxt7d0UrqTKKI+10zXPLgbRbbH0mSvwOBvY04Ih1w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

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