SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af073cb98dcc88336f59a6bf9cf147c5cac2b82d3045298eaebdd103de07deb3' 
  AND token = '5PTxgHh1fQWi2bz4Us1ZSqBuz3Xr3sI/mvPFlhtV6l8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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