SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e9b82f8345a565b3374deeae488abf59c63945070a7d72d473d24aa97473cef' 
  AND token = 'tkIpZ7d/bslaoRwRFpXS/vB3+bdS8ZnXlHpdRAeUF0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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