SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2466218ec0f5b30247c0fcb7c5bf4a6bae17ea1f9423fb1ad24f7da87cff961a' 
  AND token = 'RGszcOCwXj5sEv+S+1LPgGV9LOfkDlxZd2i5+UAQhAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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