SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fcff4858afcadccbbfdf2a02d6e38880a2edaa8112b6a7b914769874b07d91f' 
  AND token = 'RXpIW58BnidK6wm/uUyaU/2JuvFGd/PqeQljDWurAlY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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