SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0627d5a43eaa599ae162d6793609cbf92837b657f72863cf5a5fd958e1e53a5' 
  AND token = 'kdT7WHlzAu5qLlHMiKY8lSTmP7Pzr+Tv+W1HTdTfziY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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