SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9968ad2e4e191bfa9c85427ab0e0d1845911fb951d1438a24a4d78e9cc6ea449' 
  AND token = 'm/zxMbBTmDfxoveyrzlm3d45Md+ZjSuJUKivQb54rFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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