SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '48df2d309faa8eb46cd832e544d0f39b434b0ffbd8c673cd1622652c21ee49e7' 
  AND token = 'sDWqeWqvyN4dFbkGaSgiEmY+HafGZtT5jPMDPaD+7yM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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