SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fe3b75f436d141297bd5808568640495aee0ce307f2f9b4f7dc79e6ff19885d' 
  AND token = 'E25hPS8LG0psLRu50tedVA1QJWqWTvIFoGvByfvWXdE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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