SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc174652c4703e9211942cd3b0bc881328bd823fb659e921ca487a3ffd50d71f' 
  AND token = 'pPQZfesk8Ch1mQsbK7jFxy1pFEY5lPFhMgZu9F0rlvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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