SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6292cbdd2c168094084c0870fbeb0e84337ec6929ccb9aa67816da3e31f6b5c5' 
  AND token = 'UWIl7dxJWtrCwJQJkInwpVy6wkg8mBh+3OgbOft0vcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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