SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b89ba1a156af1fd29064a53fc6343538d10ca85108a3a9651e39c2623ea848fd' 
  AND token = 'lzzyAS4MdQPR+sAdOO0ti3hfXW5m96aEmurGGVH2DO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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