SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7c23b13038978eb503ece0140abeb4ab421ce29677e9c596197bbdabb708d76' 
  AND token = 'SvkzyGwSRByKOWDK61CUpfVKnsz5EBlAgayVvyiLLWU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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