SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '2ad1c12dc2407a274d9a3f3cd50b4156811d82421fa465ec15f30fc00a20dd72' 
  AND token = 'RO/wyOBqtn/NOzU7aKUI6EgEst3zzKInqZFUbTFNhXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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