SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3254f8014ec228d8fd3c683c4c92d229c29b81fe619fb179078255bc532ed524' 
  AND token = 'Zm/muYlV+oD8HjxoUdkZeZABy66FHVcBqjFpKvqcSRQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00063

JSON explain

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