SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd570419d6da67e051b6ff16a4941b5d36b35c35003fecd7341fb171c56e45a58' 
  AND token = 'pJhU5REKdnx51OezkwZ6pHIaZQSMxTiTOZuJUiUC1zo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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