SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cbfea173c6336012f99d72e434d285f8f986dba9c87bb668cd78b91fd79baa37' 
  AND token = 'bkT8GvQj/WJ2lG+4xryBDgJrqmPWfzoO2AfF6MForbk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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