SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be8197ac25a651602fdb80f0fc8c5dd2aa4bea33e3992871f09a23641c710524' 
  AND token = 'd+t5KwCBQnYg2BjClpX4azusKbs6boFvfRo5z7cH1Gw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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