SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '758c3f206ba93e0ee66865ace8c82133c5555a206ece346b69e6b255e749d999' 
  AND token = 'eZLpkTnXuiQfPBSJJmcB9Fl3XYcOTJ1r+i2KuX1yHeA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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