SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bbd176fc0b24cd1f14a9fbe0c9f72e126de13416ab4c23f0aa0c85f771373a71' 
  AND token = 'RZVjJKJ6xlwMJp1ZNfLRgjnHVU6ISPKf7/hOb5SuxkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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