SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bb208ababdad109c3595aa576b8120cd23af6fe53df15b36ae4de90ce216c10' 
  AND token = '/74eNPzStFn8Cy9wL4WLXPVSDYiI4F3PmNC0ytfccMU=' 
  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"
    }
  }
}