SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bd541de2d5cd4c34f826d1d4510d7c7cc80778cc3f1682e8ad68a5bbccefd6e' 
  AND token = 'ZfAsXjqBd3Vip4czY/108HXytVUiG9wE/N/VwZbZ/Mc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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