SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19859899bf49c9e76430fecc206482624fcea38a5395d5dde27732f26b11ec97' 
  AND token = 'cJfXlvx2zoxRroHiaPQ0nfsZifYSV8q04sPm72mQIsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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