SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7df99ef259ff91a4c823c0d7ee7c7837a50d6ffcb927703075a5cfdbc1e917e8' 
  AND token = 'XrkpNBvvO+KMocvuOXwgF8TDx69jby3dK4mo+BJW5Ww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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