SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac24fe07f3faf71aa7a4dca1f635484ddfa345f55bd487560edd250142703047' 
  AND token = 'nRdX/CJJoudw/49C7gXS6SW1vxoojQdX09ypU/5LXPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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