SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6aa9d80334ccc0c31da0749bf41ea5cadc95946456a44fb36c3352a979395784' 
  AND token = 'Q8ex6FExWy8pmUmcu8SdIowIEo4o+woRfhSUKDpGOj4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}