SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '349ddaf8c29fa0f57f789f4087a43a8bbd5792520dfef5382f35cf062fab18c8' 
  AND token = 'fq3dEw2WPhrZvDNj05myUxHCR+bBbkF54wIFAI/e5Og=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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