SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '258d11818f92edc3c61eb1184cb6a391c159e05ca815a58624a76f9e086ea683' 
  AND token = 'uP781rR/eKyW2p2N14SurjVXlfMPSsUlbrQts42b/MY=' 
  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"
    }
  }
}