SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67e5f622395535c92b26f7263fe8835144796c27ceff7457334136a5421a18dd' 
  AND token = 'tjG9l/mr+vu7UlZQexVOEfQJU9vlBrwLeaVetIAf+AU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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