SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '664300f8f0873597bf8b7c50d42b6e452d67daed83efcfbedb9b174fa66850f6' 
  AND token = 'JPOoFqzgnAudorsFKf2Je7EpLTw3zFsasKZsnp57mTI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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