SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ceee8eeeb96cd7258ee9991e4c50e09b644eabc9b31065e8557dd7042b8a6d1b' 
  AND token = 'lJ4LxBif9aw/0u1yknp7a08PkgPeTkawDzEl3oXELS8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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