SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c4afdc65df0faefdb9fb5fe6b9c1300d68362fddb6cf40db22aa1822e7a4308' 
  AND token = 'KZXdhcP7Ax9zBJUm22wlH107+c6IO4btu2EzO/Ww8jg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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