SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f839131898ec99e6f2bb11a61b553049185fe094865a711db78843617c21d896' 
  AND token = 'uZVkzfd4gRTvuan4Sa97m9Oh+YBlfLLXRWj/91+ANYo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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