SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79d2173fe9132f7d18189878be542be273f9b8441f8355431ed2a49ec4680dec' 
  AND token = 'oSgG0eyFcnzHvZx4eF85dS6eBciDOd+IcNw/2vUaO6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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