SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1cda0e9f2b408d0a62e1fa422e451072e5a16870af64537135792711bf25482' 
  AND token = 'CCUlT5uDRUJNKgI00v1rV+uWXn+oSxqtZ+7KAJzqrkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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