SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cac6eb7270b15f8b700a3ed2b8b0cb15b1ddd74c0ab0af544c394f32da3ca12' 
  AND token = 'ZmFSTSaIyjCACYIzsYn95EOBZwqOa5sBDT5ZEmlG7BU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}