SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed636b80816041ccb22b6d21090e4145a082729e7f0d27a64f930cc298d222dc' 
  AND token = 'pzaTz/ovQXJQf3bxty1xcKDNjcHeNTsj+uQH4nXGFnI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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