SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97ea3a1f3f9854fa33962d5e3baa4ec0721a434ca7e1287a66cc9b12e8bb4d91' 
  AND token = '5hq19alfYXxd/5mc9MA3fpYUTy4Vrv5f1itMp/3FnXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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