SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6688de135b6fdffa4b697a8fd97ca237e1023a72b4d174f9734fdafad57ff9b' 
  AND token = '0DgDzoqWXMQB9zYj/SwOES5eEZgQ+oRAG7DciyZp1uA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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