SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68d0c7fd7cf2f0a2ebd3fe5a29b2c77742cfe75afaf41a83ad2beb1ba151b8b6' 
  AND token = '99gFqNSKgbWstIzmNvX+TZDdpyMkrur86TcmGsqdloQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}