SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c02450f935d1695392334e98cd0e47f9448c9abf900215846b8b47f550153b22' 
  AND token = 'sS0tScwMhsAK0WijU5EWA8aRYty0eKzuezSdWMgb0v0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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