SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afe5b1566529236be1ea721238f4e32fefa95e106c9c5791c4176a10053ed008' 
  AND token = 'E33y/trRcEAcCjal+oWdsFjqnuV86UVuZAtEIzZS4Dg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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