SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb8117869523f030ca349514724645be0d0722dbd60170ecac8978b35790f946' 
  AND token = 'CrIaBjVnz97RgLPH+i/5nsMVWwkeQ/urlvbXSaCFZcM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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