SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca28a22220edeaf43bce18f197f1f80dffe3093610253e29f103d5822f77cff7' 
  AND token = '2ZScfpf8VJxJwttFWdMewAZiiWE5NOkyVoURq4Iz63A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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