SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89f916219fb79078ee5995b3d727dd513ff73f8cbd84da600eb911edebde1009' 
  AND token = '+qEATxzUZki4tFboNigj7nJGdvuUlhUbqVCsM7fmzaI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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