SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8e7b7f29ea8812a137f7072417751dc27b5bf67d01f9430bddd605148d88b152' 
  AND token = '++zUZbaqdMYI0ixbsqNOewHuC0VUgQflOG9ZBQq7Vto=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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