SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5224dd1431b3635e3cc656f04466002f5ca0ef223b0e1366ea1d613b4bccea96' 
  AND token = 'U6DvVtGlyj8awUNDHo1hEdkpDaIMfi9A8EgCVfUa73s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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