SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '28a2b9725c317943e3ddec68fca34b64a06fd767f2012235c30d5b99f2561e5b' 
  AND token = 'KH0PTKO1C83WMmbLtbQBt6pMwzCVd/h4MOJiVcwYAKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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