SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7787a394d33cfb4ccb8859767553356350ba4329ac260c623c896d3fadb8bd7d' 
  AND token = 'oISRaY/+nP0WkKuYID8hxtiQqCpAWAih5inOhN8JOzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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