SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18d4a4ca72b8ef65faefb8d6902da65030024eb078d3f47ef97c13a5b4681ece' 
  AND token = 'MqcPSAAmPSSM8AgXYzxxhFrnxos++esYyMK4b8sVZ+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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