SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c23bd24bd204cbcd824a27383dc245b97778d6849e4af1ac11b21199eea6bd86' 
  AND token = 'ZLwwDGmeByXFJwI+6KMociXmS+ugAs3/VROJt5qqfEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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