SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb04e35cc275e5cb686308ebe6936453405fef410d4a6808313fe98c3fd0a33e' 
  AND token = 'Zvwac+jAlqWu7db4AD4vbiXq4aMdxsq6C8GblszGDHM=' 
  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"
    }
  }
}