SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '284760e99a561e0fb0f5755eaeb3701da38c7b2698e2b02ee476c9fc0d85a5e3' 
  AND token = 'jV4EhcY79PwmwzKtFuWnzRqbMDPqJSQwz5vE7QGu3J0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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