SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4f9a618c430e7389db4df46bafd10f4bcdedff5dbfef13c3594bacb235670ad' 
  AND token = 'DGiUy14TfEGh9hgEtZVIH6qPvhN2b0bM/NsMK+wqXJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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