SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0dfacdbb53a12fb6320941d917877e18952cfa802d6eaa24eaff4721965af5e3' 
  AND token = 'pWdso2BCTdzLXirKb1hbmewLCtdzLQ/GNdIfKrCFuEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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