SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cae4db37f899e0da96675fb3492f5e2ca24f9491c1ec991c1b9e36f2d2ff7e1' 
  AND token = 'qKg2JQiEwph8I8hvS7XRfDtPazLyyZOQThdGMHlooEY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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