SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a2be601c76b2f1c21dad88bae739f3680e97743fc54dcd665a34de3bd4498fa' 
  AND token = '2gfvfmRAnOJvNIEI/JRuRX4IzoPd2hgLHmfT+pj8SHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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