SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '221a96259b902b6ed7b2d0d215fbbde6d9074d3fd7cc227f049bd5d35096eb59' 
  AND token = '6OcnU6oXzXEJPfavek/Yy+SrtJCwyGcY8pFV0vjd9yE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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