SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6686ff2dba995e7c2d38688bdacbdb4a95779225cd1944cc6c20e23e602ddbc' 
  AND token = 'r7C66wGWkiU9dS8chWQmnBYxZnCsSz6/GDwAKFEiMLU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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