SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9967f333178accb172d78921551260b04d15359b5c755dd1a0382f002e66aeb4' 
  AND token = 'WmyiV6LxcHYIgEdgZGRvAlwd4kmWyNZWT7+sURLdVuk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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