SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3ff254485dd71a0a4f5f80f57025be0adc6662680d43cd0c300b65ee23ddb95' 
  AND token = 'b0+hesp8BCGyoqqAYwnWmwKj4oIbeLzxiHGjnZYYlRs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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