SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb1337425ccfd53f3d3b4a3154c5820363ddc664c1bfb6812f528fc1a7d9d91b' 
  AND token = 'UhbYFfENvxRNS694JmwIGvrV3fHvD8ljXjBi+10/ebI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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