SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0256b386fbb22ba96497efd344cbdeae77a9d6edaeb02de983085e35951fdfd6' 
  AND token = 'Z6UCHZlo6Sbxvw+ftL8i7PCSMLWGl+cmsXjYdd/De8Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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