SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4df4ca4f7830d69559e6c80e91a454a37ade7f1df9556613afc9d18b198c891a' 
  AND token = 'nfhN5LwIbvKQ89rWllUzNUhG7FLzJdTwjGjnimlAvyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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