SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3555ac1efd7c85f6e72d337a793e60cafb2663276144cde422e31aa5f03b4d42' 
  AND token = 'GDI3bglZC0eejZTN3RGadYEmjivzIM8xSYhCrGEi0uo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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