SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef8353abdb51bd23ebc764c2ecca6ec2ce2097d19935c7668d7381a64b469c61' 
  AND token = 'o2q+VQxsMyVoXOsY/0Ep3RmwGzHUL4YS/9uuOBwqXN4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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