SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9942631e73251dbf00a460177358a1daad80c4cb10a9ad20fae091195f2d44d' 
  AND token = 'uadWwlQA/wXWTM//BBFuUYjzkvBYdKyD5CsHsa7cJxI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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