SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b800996950b9810f9ddbd9099f300e9a6e03a23d5793767369c8e3e65326c86' 
  AND token = 'UbZ3FYcs3ItPYFCsBPkadbIkTMZaLCTvWaeohdOeaSI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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