SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94deed2b402168fe4fcf6cb29b9fd2a6d10ead334d69aedb18b233a4c2264925' 
  AND token = 'vZsxPFQEkvBtjsOWQGt6KXoXLI8LhtjxPRfYYwQeTIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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