SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f02e391a6a95783453c22b9dbc24d389df4fd3d78ec5db32031f3e5661753b89' 
  AND token = 'KbZy4PpcWusnf0JXcrJPogt18oZdzvXg029AWO8ody4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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