SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56a18f92801b1080a4e15920a819b3ccfb9d380474285497b2ff7ac1baa1a5c2' 
  AND token = 'IAgFyJOI/VEBhGNRkdTP6uClPZI2HN3e43fYH53SyiA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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