SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bc06f70da1fd7aa6804bc4d633b95da132fa30af52b491bd923cb6326589dd9' 
  AND token = 'LnCyZpRNiKb5BD1lrPOWyvPetXvoPw9YrNli64Xj/tg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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