SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '879ea7759677dd7f6dd51d07ebc714aedd2da13e39faf1fe46816ae6f653f6dc' 
  AND token = 'SMxOqKdUkEsFR6rLyI/ZWVH5D82LkVO++7/irHb5EsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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