SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a16817eb6c7a45ab88fd2e2c5864ef403152f5e1db06506b682a1db85c1a4be8' 
  AND token = 'QVTPeDIkTxc5GI/oymmqJ2M35lgTfwRw2t4gAgtnNsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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