SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f12689bcf054a8684fd8657675cc48e9aa3a8685d029a890885d55144be83c9' 
  AND token = 'jiUFkvc2T/QFMgs4hvB1wDbhgwCFYZCbobB0NXDMfD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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