SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6da4c1af3c65eae330c4eacf573eee5f421de632d29741f091c40f8ceb1c7e58' 
  AND token = 'CRXMUELzudBW3PqQGMVn7xYYla9vYEQbaXv3mEbybzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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