SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adb215196a62e63ee8b52ec99a010aaeb66870bc29833d896c81cb06ab9f6770' 
  AND token = 'B+VYziEWWDQnUATYeUHm2oemKaZNQ2mNmxZoPajsvaI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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