SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d8d516b7bb085ffdcf4aad0a62434d46a4755c6550ae9a5a93c410b82794d84' 
  AND token = 'rQMjIHpaJzYyIJ6yHuq8C/PwDg1xjo+a97TThQSG0sc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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