SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b89eaf66d90de7929ca1f9a5140a2a5cac287903324ae9dc152115ed5770217' 
  AND token = 'QzHMa1Gl+S+4weNHuZUrMPILbMelJ9MbAfWLgRISbVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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