SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd03cd37f7a02cb52775a4cca801dd29a7e9a2e212ca960d1182307de348b332e' 
  AND token = 'phJavq5FuhZq0vu6bKZs+sGBsWAkUVWyYZAxFK4CZCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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