SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c964b9a71073010bf692471e039be23c08f07f4dbffb53aaf2b0ecf7c00ced3a' 
  AND token = 'HYCw0AdFA2QVvOAop15wXefL31eQ6PgVnd6EPVcv3ts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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