SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3be0ac23249ce15995f35b631125ed4e94ae67381518e300d9d74404e9e7188f' 
  AND token = 'Amet4+7nT+uY2wOwW0gq8vEqgynHmY0SsXjM2nEWjQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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