SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '99dd28a6213179b1be592706d23d3c2a5973be8641e495ac95685bf3efb53577' 
  AND token = 'WkZYqenIKoUsXVVhVn+gBpU+GLJQoBseZrFEU9naUoU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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