SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5cddfc4579594cd80aa3fff9a0ed8b133546c41724d5c0abc7fc6945266b829' 
  AND token = 'p9PtYTmj3wNTZyWkuGueoglzV9DmuevgKv0qYS1pwC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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