SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5536df24086d7449546ed559a5b97c5e77be65b5774e56beca0b2773b67fb19b' 
  AND token = 'KmNHlvXlcBt1H1APglehcKU9V4Edp6ujp8X/K3uPWCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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