SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47a7a28e9308b2553a8af0839818ef1113b567963c5d99ef286a203c9938f339' 
  AND token = 'hneOf6LGqFYFyfneMolPdNNd/5DmzEpxGkWkjcEElKc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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