SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e98f28a799b5499ba6802b1f8ae913950d068e80563d896271b3f9fefdd04f3' 
  AND token = '9iBo7b+RBiwjolE7JoQhKlnQVUdTfNaRFNMrnaaKSWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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