SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cbad7cc5dafb1943787deb39643eb9e3beff6d6dbba69eed530432aab70ff4d' 
  AND token = 'v1wJqb3gxXJTxHUZ6o2bFAZMNjXz5q29byZDd99zknY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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