SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46f1fd516b4aefecd5119778e06381e5c605b34bfe092f3078cbcbd86bcf323b' 
  AND token = 'mcRJHBYpvXXQ3Kh+p3pnvatSNbkMmDjWmPoQdIyX9Pc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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