SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd643ae1a645516fae3f5eec964b45b9990186ef297211ab4e39e10db629955fc' 
  AND token = 'yswqsxVxoS7wETGTDrK9/p/+MjSszlidIPtvmJw84QI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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