SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c40db984baa08ea08dc142c2e450718dc3351dd4108237aa6a3abdb69e2fb55' 
  AND token = 'HWqxXaFyl4YPyxOBrlKylWGnpPaMLInYk4qyuI5ILPM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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