SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '98be5a712a259b413ff61bac0d0db49362337351338ed09ab2962fe874af77d5' 
  AND token = 's+EZiJqVQzfgyGnGucS6G5DQCu8lkLyWqCY/dcnhrQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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