SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f76055988a2f48bd21d6673bd33a393d6d584323abfe0b3a26dbc29372eb4151' 
  AND token = 'o7Z1sBSn/72v0Pq5raxqSdtVudywSRySdkD5o888tZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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