SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be01c3b811e8deccd97594fcdb2735140983306f18d3c7bf6edb9dfddd45e0c7' 
  AND token = 'jd/qZ8Jdb4MBLKghmdYU0aSbaIdvCSZLF8MkOJagTa8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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