SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be441ff158ea4cafef73281ea3588b841d3acc1077441e96a2fedbaa6207e1cd' 
  AND token = '5njIEykqC+UjrrjH7Wn6fd4W3MXRqRARRwuXfeowTW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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