SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5450c558eba761b49b38dcc7a2eb3b393bfd48340a69f3989fc2586f3ec7f22b' 
  AND token = 'YL952hhDIlWAVqgqUpOJHpcjdZn85p1OHhW8Z1UuxBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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