SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4f8894d7457c227e46f6072a487677c4583ef97303f979dcfe89246e222d3f9' 
  AND token = 'A54MH3VwFByOMdvQ/lJzc3GUnvv0WIrdypCEYVsw+ak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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