SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c2009bda62062e345cf7103fab23d7547e349cb941104f1b4cc772a56141d16' 
  AND token = 'juyrGtfVwND6yOJSKM8iFeKKxZlUUblT+1nYt9PKlZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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