SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c169517df924cb1d7871c9106e6c0ee876e1f9676c4483173324ca59f5c72f15' 
  AND token = '4bMwNuX998kFdmyObrCkXLiXyh+xZMx2cqY6NhKAfsI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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