SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '83c6b017b119658fe0395592dfe9edc4826af479bdd0f9d6e702566b0808d8c9' 
  AND token = 'R+NuZmjASFgDwNezJ3/JtDOjulHOXKRn/Pq7E7R90qI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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