SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc16f763b73edd785a936d101c5d8ce8b8f68b83dcd2f09514cb4c746292bf84' 
  AND token = 'u6oJCC8uU/1k8sEPU+VNUQR5eERsAtzxKcZP7JTIbi8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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