SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df18099cbded8190dd4e1b233e3d0936027bd8a70367c207df702a7f21d20bc2' 
  AND token = '2ngO3rwBffyPDofrQTEKChJcXaHmpYHFrpfz9ts1BiA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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