SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bce99cd77f10b1531b28f15f8aa318f61b65287c939b2a78730afec2e6406c42' 
  AND token = 'JFjDzJCdDXqZR/3Td8gdhDnDO6VDXC7KJYT3IYh+i5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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