SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74e9589fe9b131ee4462a2465460285cb1c9c4c01201b466b41f7f700d48527c' 
  AND token = 'OAIFjpxW2bgiWjl9ptW+7rNxtc/OIW845ch2zf1fDpY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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