SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98d47003991d9c4a6fc2fa59db86068ffa6ddf59388c621b2a5824fda1490c1c' 
  AND token = '00g+B9bHBGBzFQrt7ES8XSJ76FElvKwZxduXj70yFmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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