SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fc33f1ed9c39fdb7ef9577560b28d028274b40279009ad0e5db6376c7ce33cd' 
  AND token = 'gCRoEKsQPwErcyiCb5h8LWuNHk49ceZH+xWi5rJC8JM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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