SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '320ec5551bcc414da0ab9bb1b315b5ac6881e5cd6a4e35358e53c87ad5dcb1f2' 
  AND token = 'j1uqMchiDwej3hJO6mvhfVXAXbsFLKwZrXWvS+D7nV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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