SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34ae6ee2b683cc9cc6d54bd1dbb001f6182c84f9655314fef8cb18108a91b4f1' 
  AND token = 'cXUmLBuJGcSt3NURwKWo2AW/vDD/9fjpoaOJeBzvGqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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