SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3889983cee74cf719a0bd50be7b325ae309ce8f1d42c7c85d6fc7fde39207817' 
  AND token = 'JL75vhlRHOsw3H4onw63xaUHscAflRVhu0UOO/DFuN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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