SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a17d25eb8935cde177e7af1a44bed928807a7942570df8480e52d7a20a36186a' 
  AND token = 'nIynkjvNKnkeRxCXUooFmFqq/NxneoIsTyXsXVM9u0M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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