SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7a7591de785ba2b2eac8b147ff02874ece81fdc4f86426751db3c2cd59b4a27' 
  AND token = 'kLPVs0XSVqMp8aoLGUP0DCsPCOlWJeuc65QcorOv+ms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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