SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe32002ea4b91dc3ceffc1c1341f34f45d660df29c66002cd012291b4cd221bd' 
  AND token = '8HYsQMtxLZTVnduolXPdmrwmvXsALBklCm6KHqWoL1E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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