SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7c5c1670f509054dfc907be35bce7038d6c65be98ef081d8daefc835391d2a3' 
  AND token = 'WGdkPAub7L5YUqZg/jHYdczpKmtw8JhCvQV6hpaR+To=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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