SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ccd54656617cbcf093ce6ccb8904bc4c0966f5b3964d9a571f79579cdcb79dc' 
  AND token = 'z8fFnzU+vRCCgTOYiO1cM0x7PeXWPcwRzCEuohRDxuA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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