SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '269e2368c09c978684b4a508a10486cf82f9a7d3a712738d4032e15181f54def' 
  AND token = 'voHq3MtsLafTJlhm5HRsAsAKroU3JdRzJa8mSqKBIK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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