SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4b8804d3511364ef810ac5ca69e5f6d2ce0f12faddbec75fc4514f10a025ae36' 
  AND token = 'qwIyjLwMiQcq1VDXq0MncETuoYUVpVXdBPdLpYfWWP0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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