SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2efd1a51017bc1560e16b2b6f3dc81bfe373c95749e80493ef708694d84eefdf' 
  AND token = 'YPu+MHPwqfvMzwHVefEtPi1PA4ujOPXWv/eD1QbDGmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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