SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd41ab0f4da5202244b103d776c392ddc908c3f0574ccdc2f5381f9a8799f17f9' 
  AND token = 'ftK89WnBV7TWZxeINgmyRuviS9WhfxzcOcnCqaAPnGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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