SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '350facfae5103c19a7f2ad7c4f1928a9449b5df0bd1187bf5647dc6cacaf4cb5' 
  AND token = 'NnJAYhNCFnc7RZv4lw99qBUBKCN6mbNPKL6rvt2Eceg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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