SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85cb573e80bbf3d5313edbd5380ddbd954db0033d482346c39b52329bfda53bf' 
  AND token = 'IAeMbqK4cuBD13aw08v+noRUI25jHZ0Lp//RQPbkDTU=' 
  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"
    }
  }
}