SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54ded0e3dd3604960fb038b026fb6274b648d48a9a6ecbac4944b3ec472e2e28' 
  AND token = 'tSac+yeCIl5CkDRxORdYOhEXJQmCt8EvS7okPpBlcHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}