SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '51a65803d6eec2d4e426169650c528eaa21589257e1f725e9ab03d34edcee6bb' 
  AND token = 'eZrXazA6hWmOCZ1YX/6mUTedbe3HZJ7lWuerPPIjbxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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