SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5671fcf5a13e9d75fb322a18dc875718d9e8d334051b29ca1417cf002ff840f4' 
  AND token = 'IjOCdZbrduxgNiL+Pmgd1RaG+lxhXz2WVzZYh/mv9D8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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