SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fe623074736a05f2eb39172dec8a4eba1dcc5af80a8db59127d2e7701265af8' 
  AND token = 'CQn3enDqvE3FktFWxG0KzLNs/jxe+YQpk0TuJ2srFIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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