SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c761dc8c72d5a6875b6cc4b21ee2daa59a111c89d86e8cc186012e4f64a5bf8' 
  AND token = 'RRtYRDMV9Vf5uMhQGyDtxEp5b2kIIO77YJ41XnNqgfg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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