SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '409aba8d4f39c11e4df23833886e148de3df37f62f57592fb03af0c3901f2110' 
  AND token = 'vN3uTraRD00ymCuxau9o9W7SPak9Jew2m1djMuvr50E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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