SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eee9b50be446c59811767d4a88c4a9a00b96447411ca5eedbd4fa5ee243b434a' 
  AND token = 'hDCJw5NHeJQvnUDK+cUW5woDM1zrEnIS6InLogYSuUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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