SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d8d6296ae290fe3df8bcb670fc54d8420ff59c1172c32b513d4c44727d188a0' 
  AND token = 'KbXiZy9GxTj+/d7B0tVhT6Oeh3Jup/J3yGkVhoO5k8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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