SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d99e8d5d23874dbb03ad9e7544a4f05f4c22415e65c327feafac92531ff6400' 
  AND token = 'j/48flzWXvgcrxHkz9VKLJkQrxhK4wiMvifA9DhbnxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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