SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b3887090d1b41c12a80bce7416816889919add6cfc5d139f8eb8f67626ca929' 
  AND token = 'YrLfarqejv5g2qjJk7DExihD752anl9TrYSiLwccDco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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