SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15b65ea0d96280db2a508a0917985e776dd06c70fec0d8c31728d8eca60823d6' 
  AND token = 'peKagTyonh8tUF+L/bHwUu6RfjNIWzTlAMqzgli0Tk0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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