SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7bf591b64cf57412595506ed9d3c3a4c7852bfdc9d2fd552304fa7401c9dbd8' 
  AND token = 'hYo7CJf3AePlSv2vqzOZmHSbfhcpCRAa19hxR72uG8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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