SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3cc6f1c8495101f9b7431046b7b84ba583c392d410c208adf19678d721479a2' 
  AND token = '3D1ZdnBDg+qJFB7gqFTTZaXLNSZsHi7hqQDhU8itLz4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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