SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '309fe6adf19fcd5bd40ba4b02e30c62d4df27f253dadc3b2f74daee15cc7efbe' 
  AND token = 'Gp4cadnAReWCJFylzjCBppuFT8avXaMYazmlfUsqY2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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