SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a3a5398ef164083bc7b6fda8ec2d2d15070d20bc2ba0c28d7ed68d41ae58811' 
  AND token = 'jAlKrf61FtVKi3Bzbgg4nbuhq1OosYI9jVKT+cHUmGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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