SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '581e460e6f1e907b3aa6ae85fe4cc4a0bff26d5045916e0a474f5b21eb9c7c6f' 
  AND token = 'KONCmQSJ/Rz7q9vDGwE0+W5oPqHuMzJYMR18Epjtk7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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