SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3f9494c763b8f7bec9254d526d3259997f615e97d01d68abc8c136a89c0269e' 
  AND token = 'TIPmMUT6fRgazKvuMigpwBKsnL7sT+yYKI0EyJoKmRg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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