SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '826be5f4aca91a6778025f896dd2cea1d45cb7081ce88925f818df36e81ced9e' 
  AND token = 'X1ZMCS7PQZhwfsbek31B1NuRWH3ybyMkEM2xNf8hVEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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