SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea575f6dd7af185e36a7a4fd7721ae3ff71b7f9fcba74a845dc0c262755ad94a' 
  AND token = 'I+B6NlmRzrJFRs34uzBzkAteceoQtNicxGIN//VXJto=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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