SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ed6f5c01aa9b82f24b972c6baabde69716f57c5706db2cb9f53c5688dd76edf' 
  AND token = 'phxaJlywfxwUpbLjBBDi+7o5hm+DWqrSrfNiLAF7/ZA=' 
  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"
    }
  }
}