SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8928474deffdd6a7685426807561aaa9f51848d7f90d666d32d7f5ac5dd5839f' 
  AND token = '4r0KpldJsg9uZac8U4FjlsjtvKK3m0uFvMqN9WQIuIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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