SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b261b64fdf9eb7a7649bad2b361e6814a1e43783ed420224fb26246793a8fef' 
  AND token = 'MyN5xDgmQrRVIEz66Ubcny3jYbW1TiwAS8dNbZEybUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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