SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d1d4250efdb2f5ee12f5cbc177c4f1668834a6d141c9be687ebdc969a581017' 
  AND token = 'g5lht29GLh8LiHBcX/ViefnWdgg9Su9+rFwRy4C3Hxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

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