SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a10406cd447292c6be4347d1254c79bff752bcaed98bbf2a45348266e19a1d07' 
  AND token = 'pprrL5mekd5pzVch4ApRHRjG1lFZWVyAFwDiqwtJiBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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