SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efe066887db3908e9532a72b359d6977c0c762f41400f43611df7c8df6a21758' 
  AND token = 'JqVNPoF3zQBA+eRMWDRx4tPokdQSFtCLw+XDpDkKXVM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}