SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfa5a4a66aa1728618823948ab4c6d1746397eec061c85e05b61ca12c0e5afc6' 
  AND token = 'KUCuuX27j6bwciUKJCN8luqPliLgoRfLW8AHPcYtrJE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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