SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4e6af4f8f948f46705c969e8160ea466fe01baf49352064d4c32d78117ed3f02' 
  AND token = '2/HA/mgTm1wTox+RxOpW6Ogp2S7pspn/KtchDYRyGzY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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