SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ebf117a2801363bdf467516a408e6169f3e82e2f7b30d4c76b7f261a1258280' 
  AND token = 'wjqT7QFzrPpPwUyBjx9SZcuMQy3w+/XpNe/3xlUmoLU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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