SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc4e8856b453b835a7f49188afe271a6b2158fc4afa22a67c904f1ba305ed88a' 
  AND token = 'w7jWBzmlj+nSIwduX/fyPr6gGxFhYHSQJSognSp11V8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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