SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '436ce9140b7cfe571552f4639e80df3e30ff942d86bfc7ad71503f31398e5141' 
  AND token = 'VbXZJFC1piUpZsVAUv8JmYCNYqR7hz31rvt45rq0yBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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