SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d0b3461516295883997ce6959f0a5ae00d43273aae346e2f5a3a2d8b71ee9f7' 
  AND token = 'Iwf6FJCUJXEpK1mto8dId6jbmG56iNJ1YANxazGue58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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