SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76166bf5e772aa82aae9cf66ee47adeb7de9b57ab37f64304c237072ec6d797c' 
  AND token = 'zhZor1v9RDc3Pgg5wqiaWTXdfQUx9BFARwA8VKXRIdg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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