SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0af1b5c5ae88a5fa1216b260195f6be8622e70e890066ce6d8b21c8269e4b336' 
  AND token = 'muwVS5X7BhYB56Jz4vquhFQ44HHf0IjV6d2HgOIZSy0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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