SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a72cd671e86d921509fcf6f8435bad3d7390cfd47cf34c63871759fe1f68936d' 
  AND token = 'zNGfESNhibgJCB7VsAkBemcjIWcROO0sYtq8HK+WAxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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