SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'a661a7f390839229d3b957848865c5b9e7e22b0ac052f18ff0da6f1961c3e7c1' 
  AND token = 'EvSWHFsqKZdD92DkIv92r6Xta6Ob8rKnIlhSqPDYKcA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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