SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '83a8e90a8f29e0bba6eb34708af9c0aedf03d818011974805d1797eb6851f374' 
  AND token = 'VfGVQQEY/h+4hMIORwfF2oyYitXFZLId0XxEXwL/MAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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