SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd59e91d108cf51b8e70e30c404824e19e26647549a20d5e35c37e446bc5723a7' 
  AND token = 'MFScTwavhx3TEf1TkGEIxMLmWwqv3Okv8YoJkb+RcTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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