SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a4c734b39de6466ca92a2b8fbc89c79858a20d4c106be4163e625e08af60fbd' 
  AND token = '0Rz1gWX+xTQ+IFoBLCI2CwdeJ7qah3Ns/Sv0BhgH++M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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