SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37a334b1c7656ed21eef998c3f1be95229030570ebadcfeed8b48d3b399cf7b5' 
  AND token = 'X6lKSMMiVKuS+PDyggzuvY5JlZp9JWPoBJgBDOmjTFs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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