SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fda0462ea02a3c35afd1cd8b64ffc6c7571e2a9a8a0e49e3fad536f702136b09' 
  AND token = '2V20s5dNSVerMpNXxhfHsq/WKFEnWotl8yxv9Abct/8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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