SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38316fb527bbaa131020abae002207b3ddb5795f69a27ce9024c775d1ea6f4e8' 
  AND token = '4kYhuOFfKpaveJoB5MltM/EkOi7VWhdlOydeya3qTZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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