SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fa08cecdf8b8c19298c7422b0baca2746a5e86122f6dff35b74b44876ea9395' 
  AND token = 'JkRHPu3gKv0v+FBRrNXU7LF88mkNrmxVgGxGrZ03OgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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