SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd20f8c6132d4440a2b693990627ac193eb796f61970438cdb667fc1b897c9aa' 
  AND token = 'D1jvT7bl9BgCKqHU/qM1hWttvth2TmwkUZkTxik+P5A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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