SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc63c3929801064e106342ea01b30549a285c990e9c87c80b5bd86655be62fe4' 
  AND token = 'qSv+it6BoRH5m3MzUjcyvGyactxiVaYIQwvVZv0pJRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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