SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e72fc4748c5309623b4ec27e10099b381649bf87a441277c1f7c229ebb910869' 
  AND token = 'FH6x+BcxDQWxCSIUI7pkwCqAbfCROkIZOHFr7Om2UoU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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