SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ff83e82374013b400bd92e4ca63b2496348da9e47b63885f4353cb53f783bd8' 
  AND token = 'YLIG5/PEZ3CWhskgkgsT92XEmSOsiWbOQOkzFwo+pVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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