SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc4708f95700ff6c6af0359807020be69243534c243ac4f4d6dcffdbbb599597' 
  AND token = 'Xvigm/RzQrfvrWBhTKTgWERdODQzPXIMKZ2qkqdcc9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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