SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56e42789f3f3f655ee1f607ddde7853d943007a6091fdc4fa72309adb77e784e' 
  AND token = 'VTp/TRNSAWWjG5OWkKxJqNN51VIPvkEthNTz2MA7w+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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