SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e8bf491e9ccbd7ef66eec59d5be74d7d0327c3a325a82224c4678915d12d817' 
  AND token = 'qCfX+FABiri1qZ1OsJhZACzUyEj4Kl9taMvcFh7hYZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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