SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35aa6f98d46b17174720d33593230efe60bfb6ae714b4711840a4cd35375b7c7' 
  AND token = 'a4NFpVh+yZ2GS9wjeGpqVWJkdsrp4Ii/7YuRG5+8M+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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