SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c57c71338876fdbcfd1b7d063889855cbf7d04e923e4090f0a64b723c8662fa' 
  AND token = '2PqFYz4472ZcURqHkToxypFhUwPkNud9VV0hiKviX5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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