SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91322e04c2757b1941bb40e08ac663f0c09f9afd7eb2240acfed3dc508ea12ff' 
  AND token = '8CWd/pQSdAzV2yTcwcRf8A/aMQaQmnysHpBTsrPZOHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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