SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f0dc3b2eb88056d03ad9ffb9f7112f30c9569c4d7ca62e209196467a8fb4410' 
  AND token = '0N+1KqZYqhGsLpXRt0XJdXFhFj+moTP0/smwW/k2Tis=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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