SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '412c93276a76716d3fdc5ac47a8f639889d91a5596a5b5cebfc2211db32eab22' 
  AND token = 'tU2y3+pNb6aJEejd5czVAX2PdNuRG/I9BzkOAfPIH3c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

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