SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e67a019e3a812982a6b5222e6e73f04eddbda5d99dfa9b7abea3ac89322fd62' 
  AND token = 'Y1OjiY5rnbgGg+usO5cBfkNZDQQ9zapLt9cv0gOIO/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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