SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '830401395ba73f956aa6929d462bae7cfb60445850c721881e020c80e0d73c85' 
  AND token = 'zPO5bl5qPYTo9wts3HNNBBkY+25ei3suW+MaIEpQe6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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