SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adf6ec9c5fb00369914eca9a17bb8ffdbc4a256915368d3bb6f151bc89e8dae7' 
  AND token = 'ALTQEEsP+DJAh/lUJtHcWEcP24bYOmenwbJsBpXfMGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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