SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4a6e9978541e3a5035ca805566d2cf385688bd7c7c42a330ae754b781cd2df9' 
  AND token = 'Mh0zx5DvKJymwo/RtxoFoy7C3Muv0+nM8oCXSCq/vA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

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