SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52b0d7f1387c36f74dda1998688f378813deac8e73ab8e6fd6b182db6b415b3e' 
  AND token = 'oBB/TuQ0ZEIbUdBTJRa6wVCh/6o4Ieojw0+uRxEggVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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