SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ced5605d8559fdcac797da239a538b2a11ad9b9468a9eaa35a919be5dc0ef18' 
  AND token = '7eY8H0YSsY8YPYc5DUFXqrMB3BqdrVTyNEImJgWKsl0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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