SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c0501af2f58213d91268b8c57170574e3ad5504ce1803a9aa77723f3c12af53' 
  AND token = 'KMgwDJe81H5Hul1t10FsNOOEByM3nCU2nZQxFk6v1xE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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