SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e8d5a10593f13298f6ee0dd1b920c2a08100c9f2f36fb885309cff5511d69e8' 
  AND token = 'dT6RHpS6SbZ1+n95oRSk3Sl3STLC/ubrnPYYZ1aJKJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

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