SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abb8600a25cbe8ebc2169636693293d96ae7de337816acad1789b5f1f48bfd6f' 
  AND token = 'QGMrv53OBybmlWGJzlJszpiRutWtXoyFZYJrWtAqgp0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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