SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d1aab76beb4350ba6d85f8baf7cb75ca8b570fe3e4511f56f731552799000b2' 
  AND token = 'LdC/9a7Rkhb9WMc8fkqm808wLS41gV48MTi5Kdk+k9c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}