SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34b1cb4707bdfa3b5242abbb08911a4720cc2e6452e19b05166023875e5d61a9' 
  AND token = 'lxFghZDqXHptdv7XGouBZQ23npEEFpAOxE/v2gZ3hY4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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