SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '160853081bc8a6bfe6385905497b336092645a1cc96bc456baf7003709a521aa' 
  AND token = '+1zOVBOggfSYEJzGr7lZTuCIAAx8yO8mF7i97S3RaL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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