SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19740be931ae36f4bef70a3eebf9045808c625a35a39d75c44f5b663af757566' 
  AND token = 'Ebc4qFlEqHeAqUCY2/wOUNByVYG+bjcJXWotCsSpNrs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}