SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'cab11fac8d8534629e70f851c77affe6e5ba5166efe802aef3ce3b3f347d497a' 
  AND token = '+QedhORYOOijL3XTa7k1zgnXyNgPA8VNPom9ByLrHLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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