SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f93706fd78b29fdeeff6edafb182f3aa95008f9349037d3a00ce038f735ee56' 
  AND token = 'BTEnpXnUM17j+ari93SGUwlz8xoQ9v78hPF4/OkWlUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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