SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '108f4f52891b35c1272e87f6adfbe2e661c460c8f2b5e98c292b4cf913687c2b' 
  AND token = '715Oeaeuj8UOKR5chK/9IJk+IKJnRT6tZNd7GEtUYqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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