SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b8e0ec2183bf49b48f1d8a01cf88cbefacd100fedcbafea39bd123c4754bb75' 
  AND token = 'm/ACudC71OQ4r35OCPKStAeFkzdsYU4FSMO0WC+7200=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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