SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68eeb5c1bd3eea8c440dfd48c21a32077ec59f12689b87e14dcc852b993a8e8e' 
  AND token = 'CBM60doK483haQsHuMA+IW1IKspWdN4QRdvl6PNk0wk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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