SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4884de09de362920b24b367194fcc1e8f3b357d1d344a48cbabdad94bc8bc84b' 
  AND token = '1cHBiVw8DY5Un4IpSJiI672/qyOJPgxBh7l/Vzz9lsI=' 
  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"
    }
  }
}