SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cf532c00eea01f8e8d0083ccbd7990189e4bfb07d227d5aad8e791797537a17' 
  AND token = '/lNYehNjUtASyJVIhcPxdcX6RCnW6D9/5nCNoUEpj7s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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