SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f2af0b198199b92c748bfb0d21a4235c0a0058a9a5f7751e0f24e600d1f2f46' 
  AND token = 'LxMHIRT8Vr3znsXIcexOsYOnufWrfacZ6vIZm+t9hOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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