SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98ce8cfc062000af515e20afdae397d37ad55d5e54572bccfcacc8d6d054e312' 
  AND token = 'dDkgDpHwe3/zHkwx6RVV/UZqHFBkKPiYYWh/Ca95vJA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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