SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c238f8ed7dd2329da6b66e972bd95f65a9329424d8e2f8759fd5809fda1dc243' 
  AND token = 'fzgnJoJGhMutjvVvmcMYkieiMQzzTy77eVr8GPaM/n0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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