SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'caa69fabf1eed103dc54d6b6154d0b79b4f102a879cb683c8f4e9197dc93b645' 
  AND token = 'pVTQCuK/WMOXYnvRvK5qeMshRQdbKEIVOgpvX21WVO4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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