SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '06eb3a7c8fead2379afcbabfa12030c44aa1c46335bc731456ad2e3a13469a7f' 
  AND token = 'TjVoRQWlP3Lko2pVeFbL9p1C+lvj0sXM2Xo4KXgFenM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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