SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e3e9685107dd1f038e034aea0438da985e13fea8ed4504ada00cc63c2960016' 
  AND token = 'qAHXwLRKcczcTrtCkHIHBXl658U1r9DlXFNuYutcKtU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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