SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1913658072f7000f5b9edea49fb68636efe105176e243443e8a5a99564987f8f' 
  AND token = 'RO/MLMqJD2A3ITlz70bkGT97HxZTIMxqeaxlRi0tsVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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