SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c375a3206d747fa63d036bb499cf0a5042418153f23d76ebd4e67b158111c453' 
  AND token = 'ZIuKmxwl8OoDbVuSZnlojyMi94puBwq/nx1Tx+zPYys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

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