SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '159cf44583db88c6cd1dfe98f6254486b41b40e46726374956d3d2efc584197b' 
  AND token = 'g2+RXNjDuyrzNRHv07Kn4ag/XvTFgAtT6Zwj2V77SBk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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