SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '468dcb0673addf2dbe9173ae76d30d1b22075736bb069ec2dc00a8fd3f9883a7' 
  AND token = '6spj7Vp4Mp2EkDKsmp+WA5rZ7lO2lGHpub+f5nt7ZQI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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