SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb5b8020307204921f8f59c125d72abc4dc00485488ef410e22fcfdb0407b6d6' 
  AND token = 'UCUxuzOJpIUAszIlIA8EMtAehmaVX8XjjovYbKaCRgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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