SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0dc76c7eb9842a3c74d2d0d32a6c120b1e9074676070981bb5ef29ceb01b2612' 
  AND token = 'Kc9EbY3qIGP/aiGnEFMoIHLZCnNIfyJ9c44RTsuv8fg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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