SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50ad4bd0e4b4f34254718b1e3ed3024b70b03b863a3784558f9f8b884875773f' 
  AND token = 'p8YDJGq0/1KKGpqV4ko8GhYN7ays7BBlO+rJwRf6jOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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