SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a835bda7119ead42f579e1aeefea2bfca2e20a9a9e94159747d17a685a5f23e1' 
  AND token = '43e/eThJZpzBLXD4Yciqje1mBSLoXxEvkDg73XL51I0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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