SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3537f3eea02baf47029851ae5136bd4cf02eb1748bbee465fbda2239ab85db3f' 
  AND token = '3soPDkfHCPap2cc7vvWTVhH+evx/6BXayRV91KXYP/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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