SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ebb31a345efcb23679082317e64882d617f49294e1b1a344206db1ab731fdc5' 
  AND token = 'ICGmwFM6u3rT+GWAU/te7cP0ZfpPCuvycGbeVOxZHyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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