SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76b4f3fdce7c062a32c7ef2d40d33c597a71e3585bf395d4408a7d8e0c8c185b' 
  AND token = 'tdJYgnOja60WLEsmyae8KG7qfrRWZZ+P+jzjwsZ+/4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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