SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2e5b3fa609c6e8cecfcb2d8418f19cddebff220ceb3ebb6f2b0492352b7c545' 
  AND token = 'c+Uc5HUc1aYINEv7uGf98dyrP8WSOShmct0M9jPy7wo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

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