SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '84469a550ca441a62a87fba36542d488e8837800b68623880068eb481e86f101' 
  AND token = 'ygZHmBXD35EA+N2aw+ZScg+cPLvX+fdQ5Y2tctI9xaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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