SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12f9106d7998f7c4933b838699f6c229a4a6d5788167eaf53f9885fa91e402c8' 
  AND token = 'oChY1FhVKkG8un8BqpFjve9wOkpQZufezs+2sUvRuSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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