SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc89627878783df020ef173154dc4964fa83d145bc645968b1e0c42aef150dd3' 
  AND token = 'qMKjWL3QJM04QLzBLWlg0KIzT+S7dqr8DU2VovICwaw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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