SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66b34c377693d2fe88fb12a1d43d21913038745a6f12a7e69f9b1aba3023450b' 
  AND token = 'Dv8xJKhdcVJPj1SOI2BDfdPT+uNFn7tTVr6rNTZyAws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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