SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b5b1e42c02cb93f43986816c835722e1a1fcdae59b54bda692f9e7f7e7aabc57' 
  AND token = '+UXqO6Gc4PszX1GI6h36v3UMzMh9/GN5NCj1vcPJ+Fo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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